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Benzene
Identifiers
CAS number 71-43-2 Yes check.svgY
PubChem 241
ChemSpider 236
RTECS number CY1400000
SMILES
InChI
InChI key UHOVQNZJYSORNB-UHFFFAOYAH
Properties
Molecular formula C6H6
Molar mass 78.11 g mol−1
Appearance Colorless liquid
Density 0.8765(20) g/cm3 [1]
Melting point
5.5 °C, 279 K, 42 °F
Boiling point
80.1 °C, 353 K, 176 °F
Solubility in water 0.8 g/L (15 °C)
Viscosity 0.652 cP at 20 °C
Dipole moment 0 D
Hazards
MSDS External MSDS
EU classification Flammable (F)
Carc. Cat. 1
Muta. Cat. 2
Toxic (T)
R-phrases R45, R46, R11, R36/38,R48/23/24/25, R65
S-phrases S53, S45
NFPA 704
NFPA 704.svg
3
2
0
Flash point −11 °C
Related compounds
Related compounds toluene
borazine
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
 Yes check.svgY (what is this?)  (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references
.Benzene, or benzol, is an organic chemical compound with the molecular formula C6H6.^ Benzene , or Benzol (see also Benzine ) is an organic chemical compound with the formula C 6 H 6 .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ Benzene (CAS Registry Number 71-43-2) is a simple cyclic organic compound with molecular formula C 6 H 6 .
  • Page 4 - Canadian Environmental Protection Act: Priority Substances List Report: Benzene 10 February 2010 12:012 UTC www.hc-sc.gc.ca [Source type: Academic]

.It is sometimes abbreviated Ph–H. Benzene is a colorless and highly flammable liquid with a sweet smell and a relatively high melting point.^ Benzene is highly flammable.
  • Benzene and Human Health 10 February 2010 12:012 UTC geosalud.com [Source type: FILTERED WITH BAYES]

^ At room temperature, benzene is a clear, colorless-to-light yellow liquid that is highly flammable.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ Benzene is also a highly flammable liquid.
  • Benzene Safety Program - OSHA 29 CFR 1910.1028, 29 CFR 1010.1000, 29 CFR 1910.1200, 29 CFR 1910.132-138 10 February 2010 12:012 UTC www.safetyinstruction.com [Source type: FILTERED WITH BAYES]

.Because it is a known carcinogen, its use as an additive in gasoline is now limited, but it is an important industrial solvent and precursor in the production of drugs, plastics, synthetic rubber, and dyes.^ It is carcinogenic and its use as an additive in gasoline is now limited, but it is an important industrial solvent and precursor in the production of drugs, plastics , synthetic rubber , and dyes .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ It is an important industrial solvent and precursor in the production of drugs, plastics, gasoline, synthetic rubber, and dyes.

^ Gasoline (benzene is used as an additive) .

.Benzene is a natural constituent of crude oil, and may be synthesized from other compounds present in petroleum.^ Benzene is obtained from crude petroleum.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ Benzene is also present in crude oil and gasoline and cigarette smoke.
  • Benzene and Human Health 10 February 2010 12:012 UTC geosalud.com [Source type: FILTERED WITH BAYES]

^ Benzene also is a natural part of crude oil, gasoline, and cigarette smoke.

.Benzene is an aromatic hydrocarbon and the second [n]-annulene ([6]-annulene), a cyclic hydrocarbon with a continuous pi bond.^ After the simplest possible aromatic hydrocarbon, benzene, such a configuration of six carbon atoms is known as a benzene ring.

^ It may also contain the aromatic hydrocarbons benzene, toluene, mixed xylenes and ethylbenzene.

^ Refinery hydrocarbon streams containing benzene often contain additional aromatic compounds having a high octane value, such as toluene, ethylbenzene, and the like.
  • PROCESS FOR BENZENE REMOVAL FROM GASOLINE - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

.It is also related to the functional group arene which is a generalized structure of benzene.^ Accordingly, the instant invention relates to a hexa-carboxyphenylbenzene compound of the structural formula ##STR4## wherein R is selected from the group consisting of hydrogen, alkyl moieties, and aryl moieties.
  • Hexa(meta-,para-carboxyphenyl)benzene compounds - US4339595 10 February 2010 12:012 UTC www.patents.com [Source type: Reference]

^ Its chemical structure consists of a benzene ring substituted with a hydroxy group and a propenyl group.

^ Interest in the fullerenes has led to the discovery of a related group of carbon structures referred to as nanotubes.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

Contents

History

Discovery

.The word "benzene" derives historically from "gum benzoin", sometimes called "benjamin" (i.e., benzoin resin), an aromatic resin known to European pharmacists and perfumers since the 15th century as a product of southeast Asia.^ The word "benzene" derives historically from "gum benzoin", sometimes called "benjamin" (i.e., benzoin resin), an aromatic resin known to European pharmacists and perfumers since the 15th century as a product of southeast Asia.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ During 1967, there was about 800 million gallons of benzene produced in the U.S., and by 1969, the amount of benzene increased to 1,185 million gallons with approximately 16% of the productions derived from coal.

^ After the simplest possible aromatic hydrocarbon, benzene, such a configuration of six carbon atoms is known as a benzene ring.

"Benzoin" is itself a corruption of the Arabic expression "luban jawi," or "frankincense of Java." An acidic material was derived from benzoin by sublimation, and named "flowers of benzoin," or benzoic acid. .The hydrocarbon derived from benzoic acid thus acquired the name benzin, benzol, or benzene.^ If the substrate is a very reactive benzene derivative, such as anisole, carboxylic esters or acids may be the source of the acylating electrophile.
  • Aromatic Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Academic]

^ In the reforming processing, C 6 cycloparaffins and other higher boiling cyclic hydrocarbons are converted to benzene and benzene derivatives.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ Encyclopedia - Anthracene In chemistry, anthracene is a solid polycyclic aromatic hydrocarbon consisting of three benzene rings derived from coal-tar.

[2]
.Michael Faraday first isolated and identified benzene in 1825 from the oily residue derived from the production of illuminating gas, giving it the name bicarburet of hydrogen.^ Faraday first isolated benzene in 1825 from the oily residue derived from the production of illuminating gas, giving it the name bicarburet of hydrogen .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Benzene was first discovered and isolated from coal tar in the 1800s.
  • Benzene and Human Health 10 February 2010 12:012 UTC geosalud.com [Source type: FILTERED WITH BAYES]

^ Benzene can enter the environment from any stage involved in production, storage, use, and transport of isolated benzene, and crude oil and gasoline, including emissions resulting from fuel combustion.
  • Page 4 - Canadian Environmental Protection Act: Priority Substances List Report: Benzene 10 February 2010 12:012 UTC www.hc-sc.gc.ca [Source type: Academic]

[3][4] .In 1833, Eilhard Mitscherlich produced it via the distillation of benzoic acid (from gum benzoin) and lime.^ In 1833, Eilhard Mitscherlich produced it via the distillation of benzoic acid (from gum benzoin) and lime .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ An acidic material was derived from benzoin by sublimation, and named "flowers of benzoin," or benzoic acid.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ However, an alkylbenzene, toluene for example, undergoes oxidation in the body to produce benzoic acid.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.Mitscherlich gave the compound the name benzin.^ Mitscherlich gave the compound the name benzin .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

[5] .In 1836 the French chemist Auguste Laurent named the substance "phène"; this is the root of the word phenol, which is hydroxylated benzene, and phenyl, which is the radical formed by abstraction of a hydrogen atom from benzene.^ In 1836 the French chemist Auguste Laurent named the substance "phène"; this is the root of the word phenol , which is hydroxylated benzene, and phenyl, which is the radical formed by abstraction of a hydrogen atom from benzene.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ In 1865 the German chemist Friedrich August Kekulé published a paper in French (for he was then teaching in Francophone Belgium) suggesting that the structure contained a six-membered ring of carbon atoms with alternating single and double bonds.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Gradually the sense developed among chemists that substances related to benzene formed a natural chemical family.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.In 1845, Charles Mansfield, working under August Wilhelm von Hofmann, isolated benzene from coal tar.^ Benzene was first discovered and isolated from coal tar in the 1800s.
  • Benzene and Human Health 10 February 2010 12:012 UTC geosalud.com [Source type: FILTERED WITH BAYES]

^ In 1845, Charles Mansfield, working under August Wilhelm von Hofmann , isolated benzene from coal tar .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Encyclopedia - Anthracene In chemistry, anthracene is a solid polycyclic aromatic hydrocarbon consisting of three benzene rings derived from coal-tar.

.Four years later, Mansfield began the first industrial-scale production of benzene, based on the coal-tar method.^ Benzene was first discovered and isolated from coal tar in the 1800s.
  • Benzene and Human Health 10 February 2010 12:012 UTC geosalud.com [Source type: FILTERED WITH BAYES]

^ Four years later, Mansfield began the first industrial-scale production of benzene, based on the coal-tar method.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ During 1967, there was about 800 million gallons of benzene produced in the U.S., and by 1969, the amount of benzene increased to 1,185 million gallons with approximately 16% of the productions derived from coal.

.Gradually the sense developed among chemists that substances related to benzene formed a natural chemical family.^ Gradually the sense developed among chemists that substances related to benzene formed a natural chemical family.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ In 1836 the French chemist Auguste Laurent named the substance "phène"; this is the root of the word phenol , which is hydroxylated benzene, and phenyl, which is the radical formed by abstraction of a hydrogen atom from benzene.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ The plaintiffs are stating that employees are still being put at risk and could develop a benzene-related illness similar to what their father did.

.In 1855 August Wilhelm Hofmann used the word "aromatic" to designate this family relationship, after a characteristic property of many of its members.^ In 1855 August Wilhelm Hofmann used the word " aromatic " to designate this family relationship, after a characteristic property of many of its members.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ In 1845, Charles Mansfield, working under August Wilhelm von Hofmann , isolated benzene from coal tar .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Aromatic hydrocarbon - Models of benzene ring electron configurations Aromatic hydrocarbon - Properties of aromatic hydrocarbons Aromatic hydrocarbon - Members of this group of substances Aromatic hydrocarbon - PAHs .

Ring formula

.The empirical formula for benzene was long known, but its highly polyunsaturated structure, with just one hydrogen atom for each carbon atom, was challenging to determine.^ The empirical formula for benzene was long known, but its highly polyunsaturated structure was challenging to determine.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ What is the empirical formula for benzene?

^ To reflect the delocalised nature of the bonding, benzene is often depicted with a circle inside a hexagonal arrangement of carbon atoms: .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.Archibald Scott Couper in 1858 and Joseph Loschmidt in 1861 suggested possible structures that contained multiple double bonds or multiple rings, but the study of aromatic compounds was in its very early years, and too little evidence was then available to help chemists decide on any particular structure.^ Because of the low hydrogen to carbon ratio in this and other aromatic compounds (note that the H:C ratio in an alkane is > 2), chemists expected their structural formulas would contain a large number of double or triple bonds.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

^ The sp 2 hybridized ring atoms are connected by brown bonds, the π-electron pairs and bonds that constitute the aromatic ring are colored blue.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

^ After the simplest possible aromatic hydrocarbon, benzene, such a configuration of six carbon atoms is known as a benzene ring.

.In 1865 the German chemist Friedrich August Kekulé published a paper in French (for he was then teaching in Francophone Belgium) suggesting that the structure contained a six-membered ring of carbon atoms with alternating single and double bonds.^ In 1865 the German chemist Friedrich August Kekulé published a paper in French (for he was then teaching in Francophone Belgium) suggesting that the structure contained a six-membered ring of carbon atoms with alternating single and double bonds.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Archibald Scott Couper in 1858 and Joseph Loschmidt in 1861 suggested possible structures that contained multiple double bonds or multiple rings, but the study of aromatic compounds was in its very early years, and too little evidence was then available to help chemists decide on any particular structure.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ In 1836 the French chemist Auguste Laurent named the substance "phène"; this is the root of the word phenol , which is hydroxylated benzene, and phenyl, which is the radical formed by abstraction of a hydrogen atom from benzene.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.The next year he published a much longer paper in German on the same subject.^ The next year he published a much longer paper in German on the same subject.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

[6][7] .Kekulé used evidence that had accumulated in the intervening years—namely, that there always appeared to be only one isomer of any monoderivative of benzene, and that there always appeared to be exactly three isomers of every diderivative—to argue in support of his proposed structure.^ Kekulé used evidence that had accumulated in the intervening years—namely, that there always appeared to be only one isomer of any monoderivative of benzene, and that there always appeared to be exactly three isomers of every diderivative—to argue in support of his proposed structure.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ If we use the nitration of benzene as a reference, we can assign the rate of reaction at one of the carbons to be 1.0.
  • Aromatic Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Academic]

^ Major Uses and Sources of ®ccupational Exposure At one time, benzene was an important solvent.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

.Kekulé's symmetrical ring could explain these curious facts, as well as benzene's 1:1 carbon-hydrogen ratio.^ Kekulé's symmetrical ring could explain these curious facts.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ While it is true that these findings are in agreement with previous studies(29) they still could not explain the 43% of the patients who were not exposed, and still had abnormal chromosomal changes.
  • Benzene and Diseases of the Blood: Potential Industrial Exposures 10 February 2010 12:012 UTC www.environmentaldiseases.com [Source type: Academic]

^ Under these conditions, aliphatic hydrocarbons form rings and lose hydrogen to become aromatic hydrocarbons.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.The new understanding of benzene, and hence of all aromatic compounds, proved to be so important for both pure and applied chemistry that in 1890 the German Chemical Society organized an elaborate appreciation in Kekulé's honor, celebrating the twenty-fifth anniversary of his first benzene paper.^ Benzene is the archetypical aromatic compound.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

^ The new understanding of benzene, and hence of all aromatic compounds, proved to be so important for both pure and applied chemistry that in 1890 the German Chemical Society organized an elaborate appreciation in Kekulé's honor, celebrating the twenty-fifth anniversary of his first benzene paper.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Encyclopedia - Aniline Aniline, phenylamine or aminobenzene (C6H5NH2) is an organic chemical compound which is a primary aromatic amine consisting of a benzene ring and an amino group.

.Here Kekulé spoke of the creation of the theory.^ Here Kekulé spoke of the creation of the theory.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.He said that he had discovered the ring shape of the benzene molecule after having a reverie or day-dream of a snake seizing its own tail (this is a common symbol in many ancient cultures known as the Ouroboros or Endless knot).^ He said that he had discovered the ring shape of the benzene molecule after having a reverie or day-dream of a snake seizing its own tail (this is a common symbol in many ancient cultures known as the Ouroboros).
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ How Sleep Improves Memory And Cultivates Genius - Huffington Post (blog) How Sleep Improves Memory And Cultivates GeniusHuffington Post (blog)Kekule and his 19th century chemists wrestled with the structure of benzene until Kekule fell asleep to dream of a snake eating its own tail.
  • Benzene Exposure Benzene Lawyer Lawsuit Benzene Cancer Attorney Leukemia Law Firm 10 February 2010 12:012 UTC www.thepicenter.com [Source type: General]

^ (PCBs) are a class of organic compounds with 1 to 10 chlorine atoms attached to biphenyl, which is a molecule composed of two benzene rings.
  • Benzene Exposure Benzene Lawyer Lawsuit Benzene Cancer Attorney Leukemia Law Firm 10 February 2010 12:012 UTC www.thepicenter.com [Source type: General]

.This vision, he said, came to him after years of studying the nature of carbon-carbon bonds.^ This vision, he said, came to him after years of studying the nature of carbon-carbon bonds.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ To reflect the delocalised nature of the bonding, benzene is often depicted with a circle inside a hexagonal arrangement of carbon atoms: .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ This was 20 years after he had solved the problem of how carbon atoms could bond to up to four other atoms at the same time.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.This was 7 years after he had solved the problem of how carbon atoms could bond to up to four other atoms at the same time.^ This was 20 years after he had solved the problem of how carbon atoms could bond to up to four other atoms at the same time.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ To reflect the delocalised nature of the bonding, benzene is often depicted with a circle inside a hexagonal arrangement of carbon atoms: .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Using X-ray diffraction, researchers discovered that all of the carbon-carbon bonds in benzene are of the same length of 140 picometres (pm).
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.It is curious that a similar, humorous depiction of benzene had appeared in 1886 in the Berichte der Durstigen Chemischen Gesellschaft (Journal of the Thirsty Chemical Society), a parody of the Berichte der Deutschen Chemischen Gesellschaft, only the parody had monkeys seizing each other in a circle, rather than snakes as in Kekulé's anecdote.^ Berichte der Deutschen Chemischen Gesellschaft 23 : 1302–11.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ It is curious that a similar humorous depiction of benzene had appeared in 1886 in the Berichte der Durstigen Chemischen Gesellschaft (Journal of the Thirsty Chemical Society), a parody of the Berichte der Deutschen Chemischen Gesellschaft , only the parody had monkeys seizing each other in a circle, rather than snakes as in Kekulé's anecdote.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Some historians have suggested that the parody was a lampoon of the snake anecdote, possibly already well-known through oral transmission even if it had not yet appeared in print.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

[8] .Some historians have suggested that the parody was a lampoon of the snake anecdote, possibly already well-known through oral transmission even if it had not yet appeared in print.^ Some historians have suggested that the parody was a lampoon of the snake anecdote, possibly already well-known through oral transmission even if it had not yet appeared in print.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

[2] .Others have speculated that Kekulé's story in 1890 was a re-parody of the monkey spoof, and was a mere invention rather than a recollection of an event in his life.^ Others have speculated that Kekulé's story in 1890 was a re-parody of the monkey spoof, and was a mere invention rather than a recollection of an event in his life.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ It is curious that a similar humorous depiction of benzene had appeared in 1886 in the Berichte der Durstigen Chemischen Gesellschaft (Journal of the Thirsty Chemical Society), a parody of the Berichte der Deutschen Chemischen Gesellschaft , only the parody had monkeys seizing each other in a circle, rather than snakes as in Kekulé's anecdote.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.Kekulé's 1890 speech[9] in which these anecdotes appeared has been translated into English.^ Kekulé's 1890 speech [8] in which these anecdotes appeared has been translated into English.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Translated into English by D. Wilcox and F. Greenbaum, Journal of Chemical Education , 42 (1965), 266–67.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

[10] If one takes the anecdote as the memory of a real event, circumstances mentioned in the story suggest that it must have happened early in 1862.[11]
The cyclic nature of benzene was finally confirmed by the crystallographer Kathleen Lonsdale in 1929.[12][13]

Structure

Benzene represents a special problem in that, to account for all the bonds, there must be alternating double carbon bonds:[14]
The Various representaions of benzene
.Using X-ray diffraction, researchers discovered that all of the carbon-carbon bonds in benzene are of the same length of 140 picometres (pm).^ Using X-ray diffraction, researchers discovered that all of the carbon-carbon bonds in benzene are of the same length of 140 picometres (pm).
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ To reflect the delocalised nature of the bonding, benzene is often depicted with a circle inside a hexagonal arrangement of carbon atoms: .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ In laboratory research, toluene is now often used as a substitute for benzene.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.The C–C bond lengths are greater than a double bond (135pm) but shorter than a single bond (147pm).^ The C–C bond lengths are greater than a double bond (135pm) but shorter than a single bond (147pm).
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.This intermediate distance is explained by electron delocalisation: the electrons for C–C bonding are distributed equally between each of the six carbon atoms.^ This intermediate distance is explained by electron delocalization : the electrons for C–C bonding are distributed equally between each of the six carbon atoms.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ In 1865 the German chemist Friedrich August Kekulé published a paper in French (for he was then teaching in Francophone Belgium) suggesting that the structure contained a six-membered ring of carbon atoms with alternating single and double bonds.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ To reflect the delocalised nature of the bonding, benzene is often depicted with a circle inside a hexagonal arrangement of carbon atoms: .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.One representation is that the structure exists as a superposition of so-called resonance structures, rather than either form individually.^ One representation is that the structure exists as a superposition of so-called resonance structures , rather than either form individually.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Where multiple streams are combined to form a feedstock, the benzene in one of the feeds may be much higher than 25 wt.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ Most of the reactions thus far reported for C 60 involve addition to, rather than substitution of, the core structure.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

.This delocalisation of electrons is known as aromaticity, and gives benzene great stability.^ This delocalisation of electrons is known as aromaticity , and gives benzene great stability.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ As expected, the resulting 10 π-electron annulene derivatives exhibit aromatic stability and reactivity as well as characteristic ring current anisotropy in the nmr.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

^ The enhanced stability, often referred to as aromatic stabilization , ranges (in the above cases) from a low of 16 kcal/mol for furan to 36 kcal/mol for benzene.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

.This enhanced stability is the fundamental property of aromatic molecules that differentiates them from molecules that are non-aromatic.^ This enhanced stability is the fundamental property of aromatic molecules that differentiates them from molecules that are non-aromatic.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ The enhanced stability, often referred to as aromatic stabilization , ranges (in the above cases) from a low of 16 kcal/mol for furan to 36 kcal/mol for benzene.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

^ In cases such as these, the electron delocalization described by resonance enhances the stability of the molecules, and compounds composed of such molecules often show exceptional stability and related properties.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

To reflect the delocalised nature of the bonding, benzene is often depicted with a circle inside a hexagonal arrangement of carbon atoms:
.As is common in organic chemistry, the carbon atoms in the diagram above have been left unlabeled.^ As is common in organic chemistry, the carbon atoms in the diagram above have been left unlabeled.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.Realising each carbon has 2p electrons, each carbon donates an electron into the delocalised ring above and below the benzene ring.^ To reflect the delocalised nature of the bonding, benzene is often depicted with a circle inside a hexagonal arrangement of carbon atoms: .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ The second tactic requires that the benzene ring be activated (made more nucleophilic) by substitution with an electron donating group such as OH or NH 2 .
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

^ If we extend the structure of corannulene by adding similar cycles of five benzene rings, the curvature of the resulting molecule should increase, and eventually close into a sphere of carbon atoms.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

It is the side-on overlap of p-orbitals that produces the pi clouds.
.Benzene occurs sufficiently often as a component of organic molecules that there is a Unicode symbol in the Miscellaneous Technical block with the code U+232C (⌬) to represent it with three double bonds,[15] and U+23E3 (⏣) for a delocalized version.^ Benzene occurs sufficiently often as a component of organic molecules that there is a Unicode symbol with the code 232C to represent it: .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ To reflect the delocalised nature of the bonding, benzene is often depicted with a circle inside a hexagonal arrangement of carbon atoms: .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ (PCBs) are a class of organic compounds with 1 to 10 chlorine atoms attached to biphenyl, which is a molecule composed of two benzene rings.
  • Benzene Exposure Benzene Lawyer Lawsuit Benzene Cancer Attorney Leukemia Law Firm 10 February 2010 12:012 UTC www.thepicenter.com [Source type: General]

[16]

Substituted benzene derivatives

.Many important chemicals are derived from benzene by replacing one or more of its hydrogen atoms with another functional group.^ Main article: Aromatic hydrocarbons Many important chemicals are derived from benzene, wherein with one or more of the hydrogen atoms is replaced with another functional group .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Hydrogenation (Reduction): Benzene and derivatives convert to cyclohexane and derivatives when treated with hydrogen at 450 K and 10 atm of pressure with a finely divided nickel catalyst .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ The chemical releases contained benzene , aluminum silica, and many more harmful chemicals.

.Examples of simple benzene derivatives are phenol, toluene, and aniline, abbreviated PhOH, PhMe, and PhNH2, respectively.^ Examples of simple benzene derivatives are phenol , toluene , and aniline , abbreviated PhOH, PhMe, and PhNH 2 , respectively.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Hudak A & Ungvary G (1978) Embryotoxic effects of benzene and its methyl derivatives: toluene, xylene.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Benzene and 1,3,5,7-cyclooctatetraene are examples of annulenes; they are named [6]annulene and [8]annulene respectively, according to a general nomenclature system in which the number of pi-electrons in an annulene is designated by a number in brackets.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

.Linking benzene rings gives biphenyl, C6H5–C6H5.^ (PCBs) are a class of organic compounds with 1 to 10 chlorine atoms attached to biphenyl, which is a molecule composed of two benzene rings.
  • Benzene Exposure Benzene Lawyer Lawsuit Benzene Cancer Attorney Leukemia Law Firm 10 February 2010 12:012 UTC www.thepicenter.com [Source type: General]

^ Linking benzene rings gives biphenyl , C 6 H 5 –C 6 H 5 .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Benzene rings may be joined together (fused) to give larger polycyclic aromatic compounds.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

.Further loss of hydrogen gives "fused" aromatic hydrocarbons, such as naphthalene and anthracene.^ Further loss of hydrogen gives "fused" aromatic hydrocarbons, such as naphthalene and anthracene .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ If the raw material stream contains much non-aromatic components (paraffins or naphthenes), those are likely decomposed to lower hydrocarbons such as methane, which increases the consumption of hydrogen.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ The first example is azulene, a blue-colored 10 π-electron aromatic hydrocarbon isomeric with naphthalene.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

.The limit of the fusion process is the hydrogen-free material graphite.^ The limit of the fusion process is the hydrogen-free material graphite .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.In heterocycles, carbon atoms in the benzene ring are replaced with other elements.^ In heterocycles , carbon atoms in the benzene ring are replaced with other elements.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ To reflect the delocalised nature of the bonding, benzene is often depicted with a circle inside a hexagonal arrangement of carbon atoms: .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Main article: Aromatic hydrocarbons Many important chemicals are derived from benzene, wherein with one or more of the hydrogen atoms is replaced with another functional group .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.The most important derivatives are the rings containing nitrogen.^ The most important derivatives are the rings containing nitrogen .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.Replacing one CH with N gives the compound pyridine, C5H5N. Although benzene and pyridine are structurally related, benzene cannot be converted into pyridine.^ Replacing one CH with N gives the compound pyridine , C 5 H 5 N. Although benzene and pyridine are structurally related, benzene cannot be converted into pyridine.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ The suit alleges that the defendants released benzene into the air, although they were fully aware of the dangers.

^ Therefore in the analysis of risk or causation one must take into account the knowledge that industrial solvents cannot be produced without contamination with benzene, and therefore they contain benzene.

.Replacement of a second CH bond with N gives, depending on the location of the second N, pyridazine, pyrimidine, and pyrazine.^ Replacement of a second CH bond with N gives, depending on the location of the second N, pyridazine , pyrimidine , and pyrazine.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Replacing one CH with N gives the compound pyridine , C 5 H 5 N. Although benzene and pyridine are structurally related, benzene cannot be converted into pyridine.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

Production

.Trace amounts of benzene may result whenever carbon-rich materials undergo incomplete combustion.^ The resulting low benzene content streams may be used as gasoline or gasoline blend stocks to result in gasolines meeting the increasingly stringent requirements for benzene imposed by various governments.
  • PROCESS FOR BENZENE REMOVAL FROM GASOLINE - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ Reducing the amount of material passing through the sulfur guard bed may result in a smaller guard bed being required thus reducing costs.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ This is a result of the first alkylation producing a benzene alkylate and an alcohol, where the alcohol may additionally react with benzene to form a second benzene alkylate and water.
  • PROCESS FOR BENZENE REMOVAL FROM GASOLINE - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

.It is produced in volcanoes and forest fires, and is also a component of cigarette smoke.^ It is produced in volcanoes and forest fires, and is also a component of cigarette smoke.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Natural sources of benzene include volcanoes and forest fires.

.Benzene is a principal component of combustion products produced by the burning of PVC (polyvinyl chloride).^ Benzene is an aromatic hydrocarbon that is produced by the burning of natural products.

^ Up until World War II, most benzene was produced as a byproduct of coke production (or "coke-oven light oil") in the steel industry.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ The product separator operates as a simple flash separator that produces a vapor stream rich in hydrogen with the remainder of its volume principally comprising C 1 and C 2 hydrocarbons.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

.Until World War II, most benzene was produced as a by-product of coke production (or "coke-oven light oil") in the steel industry.^ During 1967, there was about 800 million gallons of benzene produced in the U.S., and by 1969, the amount of benzene increased to 1,185 million gallons with approximately 16% of the productions derived from coal.

^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ Workers in the following industries may be at risk for chronic benzene poisoning: railroad, automobile, coke oven factories, print shops, and any industrial operations that involve the production of household products, gas, plastic, rubber, dyes, detergents, glue, pesticides, and some drugs.

.However, in the 1950s, increased demand for benzene, especially from the growing plastics industry, necessitated the production of benzene from petroleum.^ However, in the 1950s, increased demand for benzene, especially from the growing plastics industry, necessitated the production of benzene from petroleum.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ Up until World War II, most benzene was produced as a byproduct of coke production (or "coke-oven light oil") in the steel industry.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.Today, most benzene comes from the petrochemical industry, with only a small fraction being produced from coal.^ Today, most benzene comes from the petrochemical industry, with only a small fraction being produced from coal.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ Up until World War II, most benzene was produced as a byproduct of coke production (or "coke-oven light oil") in the steel industry.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.Four chemical processes contribute to industrial benzene production: catalytic reforming, toluene hydrodealkylation, toluene disproportionation, and steam cracking.^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ Here, the liquid and vapor enthalpies can be approximated by two parallel lines (i.e., the molar latent heats of chemically similar compounds, benzene and toluene, are almost the same).
  • Enthalpy-Concentration Plot for a Benzene-Toluene Binary Mixture - Wolfram Demonstrations Project 10 February 2010 12:012 UTC demonstrations.wolfram.com [Source type: FILTERED WITH BAYES]

^ Populations highly exposed to benzene are as follows: 1) workers engaged in its production, 2) workers engaged in chemical industries utilizing benzene, 3) workers in industries producing materials containing benzene, 4) workers utilizing or handling compounds containing benzene, 5) people living near factories producing or utilizing benzene, and 6) exposure to engine emissions and cigarette smoking.

.In the US, 50% of benzene comes from catalytic reforming and 25% from steam cracking.^ Benzene is produced commercially through catalytic reforming of light naphtha, dealkylation of toluene, and as a coking by-product in steel mills (Weaver et al., 1983).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.In Western Europe, 50% of benzene comes from steam cracking and 25% from catalytic reforming [citation needed].^ Depending on the feedstock used to produce the olefins, steam cracking can produce a benzene-rich liquid byproduct called pyrolysis gasoline .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Benzene is produced commercially through catalytic reforming of light naphtha, dealkylation of toluene, and as a coking by-product in steel mills (Weaver et al., 1983).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Three chemical processes contribute equally to industrial benzene production: catalytic reforming , toluene hydrodealkylation, and steam cracking.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

Catalytic reforming

.In catalytic reforming, a mixture of hydrocarbons with boiling points between 60–200 °C is blended with hydrogen gas and then exposed to a bifunctional platinum chloride or rhenium chloride catalyst at 500–525 °C and pressures ranging from 8–50 atm.^ For example, when the feed mixture is primarily C 5 and C 6 alkanes, temperatures in the range of 60° to 160° C. are desired from a normal-isoalkane equilibrium standpoint but, in order to achieve significant opening of C 5 and C 6 cyclic hydrocarbon ring, the preferred temperature range for this invention lies between 100° to 200° C. When it is desired to also isomerize significant amounts of C 4 hydrocarbons, higher reaction temperatures are required to maintain catalyst activity.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ For example, when the feed mixture is primarily C 5 and C 6 alkanes, temperatures in the range of 600 to 160° C. are desired from a normal-isoalkane equilibrium standpoint but, in order to achieve significant opening of C 5 and C 6 cyclic hydrocarbon ring, the preferred temperature range for this invention lies between 1000 to 200° C. When it is desired to also isomerize significant amounts of C 4 hydrocarbons, higher reaction temperatures are required to maintain catalyst activity.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ Such catalysts have been found to provide satisfactory benzene saturation at conditions including temperatures as low as 38° C. (100° F.), pressures from 1400 to 4800 kPa(g) (200 to 700 psig), an inlet hydrogen to hydrocarbon ratio in the range of 0.1 to 2, and a 1 to 40 liquid hourly space velocity (LHSV).
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

.Under these conditions, aliphatic hydrocarbons form rings and lose hydrogen to become aromatic hydrocarbons.^ Under these conditions, aliphatic hydrocarbons form rings and lose hydrogen to become aromatic hydrocarbons.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Further loss of hydrogen gives "fused" aromatic hydrocarbons, such as naphthalene and anthracene .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Von Oetingen WF (1940) II. Toxicity and potential dangers of aliphatic and aromatic hydrocarbons.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.The aromatic products of the reaction are then separated from the reaction mixture (or reformate) by extraction with any one of a number of solvents, including diethylene glycol or sulfolane, and benzene is then separated from the other aromatics by distillation.^ The aromatic products of the reaction are then separated from the reaction mixture (or reformate) by extraction with any one of a number of solvents , including diethylene glycol or sulfolane , and benzene is then separated from the other aromatics by distillation.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ The reaction involves the acylation of benzene (or many other aromatic rings) with an acyl chloride using a strong Lewis acid catalyst such as aluminium chloride or iron chloride which act as a halogen carrier.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ The process of claim 1, further comprising feeding hydrogen to the catalytic distillation column below the at least one reaction zone.
  • PROCESS FOR BENZENE REMOVAL FROM GASOLINE - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

The extraction step of aromatics from the reformate is designed to produce aromatics with lowest non-aromatic components. .So-called "BTX (Benzene-Toluene-Xylenes)" process consists of such extraction and distillation steps.^ This is often called "on-purpose" methodology to produce benzene, compared to conventional BTX (benzene-toluene-xylene) processes.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ So-called "BTX (Benzene-Toluene-Xylenes)" process consists of such extraction and distillation steps.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ UV Fourier transform absorption cross sections of benzene, toluene, meta-, ortho, and para-xylene; m-xylene .
  • science-softCon UV/Vis Spectra Data Base 10 February 2010 12:012 UTC www.science-softcon.de [Source type: Academic]

.One such widely used process from UOP was licensed to producers and called the Udex process.^ Its most widely-produced derivatives include styrene , which is used to make polymers and plastics, phenol for resins and adhesives (via cumene ), and cyclohexane , which is used in the manufacture of Nylon.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ This is often called "on-purpose" methodology to produce benzene, compared to conventional BTX (benzene-toluene-xylene) processes.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Catalytic reforming and catalytic isomerization are two widely used processes for this upgrading.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

.Similarly to this catalytic reforming, UOP and BP commercialized a method from LPG (mainly propane and butane) to aromatics.^ Benzene is produced commercially through catalytic reforming of light naphtha, dealkylation of toluene, and as a coking by-product in steel mills (Weaver et al., 1983).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Octane improvement can also be obtained by catalytically isomerizing the paraffinic hydrocarbons to rearrange the structure of the paraffinic hydrocarbons into branch-chained paraffins or reforming to convert the C 6 and heavier hydrocarbons to aromatic compounds.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

Toluene hydrodealkylation

.Toluene hydrodealkylation converts toluene to benzene.^ Toluene hydrodealkylation converts toluene to benzene.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Three chemical processes contribute equally to industrial benzene production: catalytic reforming , toluene hydrodealkylation, and steam cracking.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Where a chemical complex has similar demands for both benzene and xylene , then toluene disproportionation ( TDP ) may be an attractive alternative to the toluene hydrodealkylation.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.In this hydrogen-intensive process, toluene is mixed with hydrogen, then passed over a chromium, molybdenum, or platinum oxide catalyst at 500–600 °C and 40–60 atm pressure.^ In this hydrogen-intensive process, toluene is mixed with hydrogen, then passed over a chromium , molybdenum , or platinum oxide catalyst at 500–600 °C and 40–60 atm pressure.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ In catalytic reforming, a mixture of hydrocarbons with boiling points between 60–200 °C is blended with hydrogen gas and then exposed to a bifunctional platinum chloride or rhenium chloride catalyst at 500–525 °C and pressures ranging from 8–50 atm.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Hydrogenation (Reduction): Benzene and derivatives convert to cyclohexane and derivatives when treated with hydrogen at 450 K and 10 atm of pressure with a finely divided nickel catalyst .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.Sometimes, higher temperatures are used instead of a catalyst (at the similar reaction condition).^ For example, pressures, temperatures, and other operating conditions may be adjusted to achieve the desired C.sub.6/C.sub.7 split to avoid contact of the C.sub.7 compounds with the alkylation catalyst.
  • PROCESS FOR BENZENE REMOVAL FROM GASOLINE - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ In April 1996, Westinghouse Savannah River Company duplicated the decomposition reaction in the laboratory using simulated waste and accelerated conditions (higher temperature and greater concentrations of metals that appear to catalyze the reaction).
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ For example, hydrogen may be advantageously used to prolong the service life of the alkylation catalyst contained in reaction zone 12.
  • PROCESS FOR BENZENE REMOVAL FROM GASOLINE - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

Under these conditions, toluene undergoes dealkylation to benzene and methane:
C6H5CH3 + H2 → C6H6 + CH4
This irreversible reaction is accompanied by an equilibrium side reaction that produces biphenyl (aka diphenyl) at higher temperature:
2 C6H6 is in equilibrium with H2 + C6H5–C6H5
.If the raw material stream contains much non-aromatic components (paraffins or naphthenes), those are likely decomposed to lower hydrocarbons such as methane, which increases the consumption of hydrogen.^ If the raw material stream contains much non-aromatic components (paraffins or naphthenes), those are likely decomposed to lower hydrocarbons such as methane, which increases the consumption of hydrogen.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ Further loss of hydrogen gives "fused" aromatic hydrocarbons, such as naphthalene and anthracene .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.A typical reaction yield exceeds 95%.^ A typical reaction yield exceeds 95%.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.Sometimes, xylenes and heavier aromatics are used in place of toluene, with similar efficiency.^ The C.sub.7 and heavier components, including toluene, may be distilled downward, avoiding or minimizing contact of C.sub.7+ aromatic compounds with the alkylation catalyst.
  • PROCESS FOR BENZENE REMOVAL FROM GASOLINE - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ The aromatic heterocycle pyridine is similar to benzene, and is often used as a weak base for scavanging protons.
  • Chemical Reactivity 10 February 2010 12:012 UTC www.cem.msu.edu [Source type: Reference]

^ Benzene in high concentrations has narcotic effects similar to toluene and other aromatics.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

.This is often called "on-purpose" methodology to produce benzene, compared to conventional BTX (benzene-toluene-xylene) processes.^ This is often called "on-purpose" methodology to produce benzene, compared to conventional BTX (benzene-toluene-xylene) processes.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ So-called "BTX (Benzene-Toluene-Xylenes)" process consists of such extraction and distillation steps.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ In laboratory research, toluene is now often used as a substitute for benzene.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

Toluene disproportionation

.Where a chemical complex has similar demands for both benzene and xylene, then toluene disproportionation (TDP) may be an attractive alternative to the toluene hydrodealkylation.^ Where a chemical complex has similar demands for both benzene and xylene , then toluene disproportionation ( TDP ) may be an attractive alternative to the toluene hydrodealkylation.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Toluene hydrodealkylation converts toluene to benzene.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ UV Fourier transform absorption cross sections of benzene, toluene, meta-, ortho, and para-xylene; m-xylene .
  • science-softCon UV/Vis Spectra Data Base 10 February 2010 12:012 UTC www.science-softcon.de [Source type: Academic]

.Broadly speaking 2 toluene molecules are reacted and the methyl groups rearranged from one toluene molecule to the other, yielding one benzene molecule and one xylene molecule.^ Broadly speaking 2 toluene molecules are reacted and the methyl groups rearranged from one toluene molecule to the other, yielding one benzene molecule and one xylene molecule.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ As its toxicity became obvious, benzene was supplanted by other solvents, especially toluene (methyl benzene), which has similar physical properties but is not as carcinogenic.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Lange A, Smolik R, Zatonski W, Szymanska (1973) Serum immunoglobulin levels in workers exposed to benzene, toluene, and xylene.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Given that demand for para-xylene (p-xylene) substantially exceeds demand for other xylene isomers, a refinement of the TDP process called Selective TDP (STDP) may be used.^ Combination processes using isomerization and reforming to convert naphtha range feedstocks are well known.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ The aforementioned separations may be further complicated by azeotropes that may form between water, ethers, and alcohols used in the alkylation process, as well as those that may form between hydrocarbons and water, alcohols, and ethers.
  • PROCESS FOR BENZENE REMOVAL FROM GASOLINE - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ Other catalysts useful in embodiments disclosed herein may include phosphorous-modified zeolites, aluminas, and silicas.
  • PROCESS FOR BENZENE REMOVAL FROM GASOLINE - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

In this process, the xylene stream exiting the TDP unit is approximately 90% paraxylene. .In some current catalytic systems, even the benzene-to-xylenes ratio is decreased (more xylenes) when the demand of xylenes is higher.^ In a study of 35 painters exposed to 3 to 49 ppm of benzene and higher concentrations of toluene and xylene, increased serum IgM, and decreased serum IgG and IgA were found (Lange et al., 1973).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Additionally, toluene, xylenes, and ethylbenzene each have a higher octane rating than benzene.
  • PROCESS FOR BENZENE REMOVAL FROM GASOLINE - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ Locally, benzene can produce erythema, a burning sensation, and in more severe cases, edema and even blistering.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

Steam cracking

.Steam cracking is the process for producing ethylene and other alkenes from aliphatic hydrocarbons.^ The process of claim 1 wherein the hydrogen-rich gas stream is mixed with said feedstock to produce a hydrogen to hydrocarbon ratio in the range of 0.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ Benzene may be present in gasoline and other petroleum products up to 1%, as a natural part of the cracking process.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ In the reforming processing, C 6 cycloparaffins and other higher boiling cyclic hydrocarbons are converted to benzene and benzene derivatives.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

.Depending on the feedstock used to produce the olefins, steam cracking can produce a benzene-rich liquid by-product called pyrolysis gasoline.^ Depending on the feedstock used to produce the olefins, steam cracking can produce a benzene-rich liquid byproduct called pyrolysis gasoline .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ Up until World War II, most benzene was produced as a byproduct of coke production (or "coke-oven light oil") in the steel industry.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ The feedstocks that are used in this invention will typically include hydrocarbon fractions rich in C 4 -C 6 normal paraffins.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

.Pyrolysis gasoline can be blended with other hydrocarbons as a gasoline additive, or distilled (in BTX process) to separate it into its components, including benzene.^ Pyrolysis gasoline can be blended with other hydrocarbons as a gasoline additive, or distilled (in BTX process) to separate it into its components, including benzene.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ The separator may contain packing or other liquid vapor separation devices to limit the carryover of hydrocarbons.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ Depending on the feedstock used to produce the olefins, steam cracking can produce a benzene-rich liquid byproduct called pyrolysis gasoline .
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

Uses

Early uses

.In the 19th and early-20th centuries, benzene was used as an after-shave lotion because of its pleasant smell.^ In the 19th and early-20th centuries, benzene was used as an after-shave lotion because of its pleasant smell.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.Prior to the 1920s, benzene was frequently used as an industrial solvent, especially for degreasing metal.^ Prior to the 1920s, benzene was frequently used as an industrial solvent, especially for degreasing metal.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ An increased frequency of chromatid and isochromatid breaks was found in children of women exposed during pregnancy to a mix of benzene and other solvents in the printing industry and chemical laboratories (Funes-Cravioto et al., 1977).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.As its toxicity became obvious, benzene was supplanted by other solvents, especially toluene (methyl benzene), which has similar physical properties but is not as carcinogenic.^ Physical properties of: Benzene .
  • Benzene | Marketizer.com 10 February 2010 12:012 UTC pr76.marketizer.com [Source type: General]

^ Technical Information Physical properties of: Benzene Safety and handling information for: Benzene .
  • Benzene | Marketizer.com 10 February 2010 12:012 UTC pr76.marketizer.com [Source type: General]

^ Ikeda M & Ohtsuji H (1971) Phenobarbital-induced protection against toxicity of toluene and benzene in the rat.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.In 1903, Ludwig Roselius popularized the use of benzene to decaffeinate coffee.^ In 1903, Ludwig Roselius popularized the use of benzene to decaffeinate coffee.
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

.This discovery led to the production of Sanka (the letters "ka" in the brand name stand for kaffein).^ This discovery led to the production of Sanka (the letters "ka" in the brand name stand for kaffein ).
  • Benzene: Encyclopedia of chemistry, analytics & pharmaceutics with 64,557 entries. 10 February 2010 12:012 UTC www.chemie.de [Source type: Academic]

This process was later discontinued. .Benzene was historically found as a significant component in many consumer products such as Liquid Wrench, several paint strippers, rubber cements, spot removers and other hydrocarbon-containing products.^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ While incidental exposure to Benzene from surrounding air is not usually harmful, prolonged exposure around gas stations or other areas where products made with Benzene are used can cause many symptoms such as dizziness, headaches, confusion, tremors, rapid heart rate, and unconsciousness.
  • Benzene Exposure Benzene Lawyer Lawsuit Benzene Cancer Attorney Leukemia Law Firm 10 February 2010 12:012 UTC www.thepicenter.com [Source type: General]

^ While it is found naturally in the environment and in airborne compounds such as cigarette smoke and gasoline, the biggest threat is from the production of manmade products created with it.
  • Benzene Exposure Benzene Lawyer Lawsuit Benzene Cancer Attorney Leukemia Law Firm 10 February 2010 12:012 UTC www.thepicenter.com [Source type: General]

.Some ceased manufacture of its benzene formula about 1950 while others continued to use benzene as a component or significant contaminant until the late 1970s when leukemia deaths were found associated with Goodyear's Pliofilm production operations in Ohio.^ In some countries, benzene continues to be used as a household cleaner.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Where can more information about benzene be found?
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

.Until the late 1970s, many hardware stores, paint stores, and other retail outlets sold benzene in small cans, such as quart size, for general-purpose use.^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ While incidental exposure to Benzene from surrounding air is not usually harmful, prolonged exposure around gas stations or other areas where products made with Benzene are used can cause many symptoms such as dizziness, headaches, confusion, tremors, rapid heart rate, and unconsciousness.
  • Benzene Exposure Benzene Lawyer Lawsuit Benzene Cancer Attorney Leukemia Law Firm 10 February 2010 12:012 UTC www.thepicenter.com [Source type: General]

^ Benzene is used mainly as a raw material for synthesizing chemicals such as styrene, phenol, and cyclohexane and for manufacturing dyes, detergents, explosives, rubber, plastics, and pharmaceuticals.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

.Many students were exposed to benzene in school and university courses while performing laboratory experiments with little or no ventilation in many cases.^ There is no specific antidote for benzene, but its effects can be treated, and most exposed persons recover fully.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ The OSHA benzene standard mandates that urinary phenol-testing be performed on all workers exposed to benzene in an emergency situation (see Follow-up below).
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ Victims exposed only to benzene vapor who have no skin or eye irritation do not need decontamination.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

This very dangerous practice has been almost totally eliminated.
.As a gasoline (petrol) additive, benzene increases the octane rating and reduces knocking.^ Therefore, processes are needed for reducing the benzene content of the gasoline pool while maintaining sufficient conversion to satisfy the octane requirements of modern engines.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ Those tests showed the benzene release rate was a function of slurry pump operation (i.e., pump operation increased the benzene release rate).
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ Benzene has a high octane number value and has been previously blended into gasoline.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

.Consequently, gasoline often contained several percent benzene before the 1950s, when tetraethyl lead replaced it as the most widely-used antiknock additive.^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ In the United States benzene averages less than 2% by volume in gasoline, and in Europe the concentration is often 4 to 5% by volume and may exceed these concentrations with certain blends.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ The feed stream is heated by heat exchange with the effluent of the benzene saturation reactor using a heat exchanger before being passed to the sulfur guard bed.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

.With the global phaseout of leaded gasoline, benzene has made a comeback as a gasoline additive in some nations.^ In some instances, it is probable that both the exposure to benzene on an industrial basis and exposure to other toxic chemical (such as cigarette smoking) on a nonindustrial basis are additive to causation.

.In the United States, concern over its negative health effects and the possibility of benzene entering the groundwater have led to stringent regulation of gasoline's benzene content, with limits typically around 1%.^ Try to avoid administering epinephrine due to the possible myocardial sensitizing effect of benzene.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ In the United States, smoking accounts for approximately half of the total population exposure to benzene (Wallace, 1989).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Industrial Production and Usage Benzene is produced in large quantities in the United States.

[17] .European petrol specifications now contain the same 1% limit on benzene content.^ This invention relates more specifically to the processing of benzene-containing hydrocarbon feeds and the isomerization of light paraffins.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

^ The benzene content in a gasoline pool is reduced by a process that hydrogenates a benzene-containing isomerization zone feedstream.
  • Isomerization of Benzene-Containing Feedstocks - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

The United States Environmental Protection Agency‎ has new regulations that will lower the benzene content in gasoline to 0.62% in 2011.[18]

Current uses

.Today benzene is mainly used as an intermediate to make other chemicals.^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ USES 4.1 Uses 4.1.1 Uses 4.1.2 Description Benzene is used as an intermediate in the manufacture of a number of chemicals, including ethylbenzene (used in the synthesis of styrene), cumene (used in the synthesis of phenol and for the manufacture of phenolic resins and nylon intermediates), cyclohexane (used to make nylon resins), and nitrobenzene (used in the synthesis of aniline).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Benzene is used mainly as a raw material for synthesizing chemicals such as styrene, phenol, and cyclohexane and for manufacturing dyes, detergents, explosives, rubber, plastics, and pharmaceuticals.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

.Its most widely-produced derivatives include styrene, which is used to make polymers and plastics, phenol for resins and adhesives (via cumene), and cyclohexane, which is used in the manufacture of Nylon.^ USES 4.1 Uses 4.1.1 Uses 4.1.2 Description Benzene is used as an intermediate in the manufacture of a number of chemicals, including ethylbenzene (used in the synthesis of styrene), cumene (used in the synthesis of phenol and for the manufacture of phenolic resins and nylon intermediates), cyclohexane (used to make nylon resins), and nitrobenzene (used in the synthesis of aniline).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ Benzene is used mainly as a raw material for synthesizing chemicals such as styrene, phenol, and cyclohexane and for manufacturing dyes, detergents, explosives, rubber, plastics, and pharmaceuticals.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

.Smaller amounts of benzene are used to make some types of rubbers, lubricants, dyes, detergents, drugs, explosives, napalm and pesticides.^ Plastics, synthetic rubber, dyes, paints, varnishes, resins, detergent raw materials and pesticides are all produced on the basis of benzene.
  • Benzene 10 February 2010 12:012 UTC www2.gtz.de [Source type: Academic]

^ Stockton RecordExtraction uses a method called hydraulic fracturing in which huge amounts of water laced with benzene and proprietary chemicals are forced into the shale ...
  • Benzene Exposure Benzene Lawyer Lawsuit Benzene Cancer Attorney Leukemia Law Firm 10 February 2010 12:012 UTC www.thepicenter.com [Source type: General]

^ In some countries, benzene continues to be used as a household cleaner.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.In both the US and Europe, 50% of benzene is used in the production of ethylbenzene / styrene, 20% is used in the production of cumene, and about 15% of benzene is used in the production of cyclohexane (eventually to nylon).^ During 1967, there was about 800 million gallons of benzene produced in the U.S., and by 1969, the amount of benzene increased to 1,185 million gallons with approximately 16% of the productions derived from coal.

^ USES 4.1 Uses 4.1.1 Uses 4.1.2 Description Benzene is used as an intermediate in the manufacture of a number of chemicals, including ethylbenzene (used in the synthesis of styrene), cumene (used in the synthesis of phenol and for the manufacture of phenolic resins and nylon intermediates), cyclohexane (used to make nylon resins), and nitrobenzene (used in the synthesis of aniline).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Benzene is used mainly as a raw material for synthesizing chemicals such as styrene, phenol, and cyclohexane and for manufacturing dyes, detergents, explosives, rubber, plastics, and pharmaceuticals.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

In laboratory research, toluene is now often used as a substitute for benzene. The solvent-properties of the two are similar but toluene is less toxic and has a wider liquid range.
.Benzene has been used as a basic research tool in a variety of experiments including analysis of a two-dimensional gas.^ This modification is essentially an adaptation of sampling probes and gas chromatograph analysis capability used in the depletion of the benzene inventory in Tank 48.
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ Information Required in the Analysis of Benzene Exposure and Hematological Malignancies Detailed history of exposure, including, frequency, duration and symptoms during exposure (medical records, depositions, and MSDS).

^ The use of chromosomal abnormalities as a biological marker of exposure in humans have become an important tool in the research.

Major commodity chemicals and polymers derived from benzene

Reactions

.
  • Electrophilic aromatic substitution is a general method of derivatizing benzene.^ Benzene's sweet aromatic odor generally provides adequate warning of hazardous concentrations for acute exposure.
    • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

    Benzene is sufficiently nucleophilic that it undergoes substitution by acylium ions or alkyl carbocations to give substituted derivatives.
Electrophilic aromatic substitution of benzene
Friedel-Crafts acylation of benzene by acetyl chloride
Friedel-Crafts alkylation of benzene with methyl chloride
  • Sulfonation. The most common method involves mixing sulfuric acid with sulfate, a mixture called fuming sulfuric acid. The sulfuric acid protonates the sulfate, giving the sulfur atom a permanent, rather than resonance stabilized positive formal charge. This molecule is very electrophillic and Electrophillic Aromatic Substitution then occurs.
  • Nitration: Benzene undergoes nitration with nitronium ions (NO2+) as the electrophile. Thus, warming benzene at 50-55 degrees Celsius, with a combination of concentrated sulfuric and nitric acid to produce the electrophile, gives nitrobenzene.
  • Hydrogenation(Reduction): Benzene and derivatives convert to cyclohexane and derivatives when treated with hydrogen at 450 K and 10 atm of pressure with a finely divided nickel catalyst.
  • Benzene is an excellent ligand in the organometallic chemistry of low-valent metals. Important examples include the sandwich and half-sandwich complexes respectively Cr(C6H6)2 and [RuCl2(C6H6)]2.

Environmental transformation

.Even if it is not a common substrate for the metabolism of organisms, benzene could be oxidized by both bacteria and eukaryotes.^ Sammett D, Lee EW, Kocsis JJ, Snyder R (1979) Partial hepatectomy reduces both metabolism and toxicity of benzene.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Metabolism Benzene is both exhaled unchanged in the lungs and excreted as metabolites in the urine.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ High risk circumstances of poisoning The most common form of exposure to benzene is occupational, and both occupational and environmental exposures to benzene are overwhelmingly through inhalation.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

In bacteria, dioxygenase enzyme can add an oxygen molecule to the ring, and the unstable product is immediately reduced (by NADH) to a cyclic diol with two double bonds, breaking the aromaticity. Next, the diol is newly reduced by NADH to catechol.
The catechol is then metabolized to acetyl CoA and succinyl CoA, used by organisms mainly in the Krebs Cycle for energy production.

Health effects

A bottle of benzene. The warnings show benzene is a toxic and flammable liquid.
.Benzene exposure has serious health effects.^ What immediate health effects can result from benzene exposure?
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ Did you know that the toxic effects of benzene exposure can show up as late as 29 years after the first exposure?
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Repeated exposure to high levels of benzene (≤200 ppm) can result in persistent CNS effects.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

.Outdoor air may contain low levels of benzene from tobacco smoke, wood smoke, automobile service stations, the transfer of gasoline, exhaust from motor vehicles, and industrial emissions.^ It is found in trace amounts in cigarette smoke and drinking water, as a contaminant in some industrial solvents, and as a constituent of motor fuels, unleaded gasoline in particular.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ Environmental exposure is greatest in areas of heavy automobile use due to the presence of benzene in tailpipe emissions, near service stations, and from tobacco smoke (ATSDR, 1993).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Populations highly exposed to benzene are as follows: 1) workers engaged in its production, 2) workers engaged in chemical industries utilizing benzene, 3) workers in industries producing materials containing benzene, 4) workers utilizing or handling compounds containing benzene, 5) people living near factories producing or utilizing benzene, and 6) exposure to engine emissions and cigarette smoking.

[19] .Vapors from products that contain benzene, such as glues, paints, furniture wax, and detergents, can also be a source of exposure, although many of these have been modified or reformulated since the late 1970s to eliminate or reduce the benzene content.^ Plastics, synthetic rubber, dyes, paints, varnishes, resins, detergent raw materials and pesticides are all produced on the basis of benzene.
  • Benzene 10 February 2010 12:012 UTC www2.gtz.de [Source type: Academic]

^ Benzene is a chemical solvent derived from petroleum used to manufacture a wide variety of products, including inks, dyes, plastics, detergents, pesticides and gasoline.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Benzene reacts explosively with strong oxidizers, such as perchlorates and nitric acid, and many fluorides.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

.Air around hazardous waste sites or gas stations may contain higher levels of benzene.^ The low-level decontaminated salt solution will be fed to the Z-Area Saltstone Facility, where it will be converted to a cemented waste form for on-site disposal in permanent vaults.
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ Because the benzene has a higher molecular weight compared to air (78 versus 29) or water vapor (18), .
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ However, these concentrations may be decreased markedly in light of the intended changes in acceptable workplace benzene levels for 1993 to 1994 (ACGIH, 1993).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.The short term breathing of high levels of benzene can result in death, while low levels can cause drowsiness, dizziness, rapid heart rate, headaches, tremors, confusion, and unconsciousness.^ Even short-term exposure can cause headaches, dizziness, confusion and sometimes death when benzene is breathed or ingested.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Breathing benzene vapor in small amounts can cause headache, dizziness, drowsiness, or nausea.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ VERDICT Exposure to high concentration of the chemical Benzene in the workplace - temporary breathing and equilibrium problems and severe migraine headaches continuing intermittently -inability to continue work.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

.Eating or drinking foods containing high levels of benzene can cause vomiting, irritation of the stomach, dizziness, sleepiness, convulsions, and death.^ If swallowed, benzene can irritate the stomach, causing nausea, vomiting, and diarrhea.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ Even short-term exposure can cause headaches, dizziness, confusion and sometimes death when benzene is breathed or ingested.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Repeated exposure to high levels of benzene (≤200 ppm) can result in persistent CNS effects.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

.The major effects of benzene are manifested via chronic (long-term) exposure through the blood.^ Even short-term exposure can cause headaches, dizziness, confusion and sometimes death when benzene is breathed or ingested.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Did you know that the toxic effects of benzene exposure can show up as late as 29 years after the first exposure?
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Despite its sweet smell and colorless appearance, benzene is known to cause leukemia (bone marrow cancer) with chronic exposure, as well as anemia and immune deficiency.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

.Benzene damages the bone marrow and can cause a decrease in red blood cells, leading to anemia.^ Benzene is a myclotoxicant known to suppress bone marrow cell proliferation and to induce hematologic disorders in humans and animals.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ Despite its sweet smell and colorless appearance, benzene is known to cause leukemia (bone marrow cancer) with chronic exposure, as well as anemia and immune deficiency.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Baarson KA, Snyder CA, Green JD, Sellakumar A, Goldstein BD & Albert RE (1982) The hematotoxic effects of inhaled benzene on peripheral blood, bone marrow, and spleen cells are increased by ingested ethanol.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.It can also cause excessive bleeding and depress the immune system, increasing the chance of infection.^ Benzene may cause central nervous system depression, cardiac arrhythmias, cutaneous burns and respiratory irritation.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ Benzene may cause central nervous system depression, cardiac dysrhythmias, cutaneous burns, and respiratory irritation.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ Benzene may cause central nervous system depression and arrhythmias to persons acutely exposed.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

.Benzene causes leukemia and is associated with other blood cancers and pre-cancers of the blood.^ Despite its sweet smell and colorless appearance, benzene is known to cause leukemia (bone marrow cancer) with chronic exposure, as well as anemia and immune deficiency.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Haematological abnormalities, especially anemia, leukopenia, thrombocytopenia, pancytopenia, or acute myelogenous leukemia, associated with chronic use of benzene suggest benzene poisoning.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Chronic benzene exposure is associated with an increased risk of leukemia.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Human exposure to benzene is a global health problem.^ VERDICT Exposure to high concentration of the chemical Benzene in the workplace - temporary breathing and equilibrium problems and severe migraine headaches continuing intermittently -inability to continue work.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Occupational Safety and Health Administration: 29 CFR Pan 1910, Occupational Exposure to Benzene; Final Rule.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ Sherwood RJ (1988) Pharmacokinetics of benzene in a human after exposure at about the occupational limit.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Benzene targets liver, kidney, lung, heart and the brain and can cause DNA strand breaks, chromosomal damage etc.^ Autopsy was unremarkable except for elevated benzene levels: blood 0.38 mg%, brain 1.38 mg%, and liver 0.28 mg%.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Pulmonary aspiration of toxic vomitus or ingested liquid benzene may cause severe hemorrhagic inflammation of the lungs.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ In human autopsies on individuals dying shortly after exposure, high levels of benzene were found in the brain, with lower levels in the fat, blood, kidneys, and liver (Tauber, 1970; Winek & Collom, 1971).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Benzene causes cancer in both animals and humans.^ Benzene exposure can cause chromosomal aberrations in animals and humans.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ Benzene is a myclotoxicant known to suppress bone marrow cell proliferation and to induce hematologic disorders in humans and animals.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ Despite its sweet smell and colorless appearance, benzene is known to cause leukemia (bone marrow cancer) with chronic exposure, as well as anemia and immune deficiency.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

.Benzene was first reported to induce cancer in humans in the 1920s.^ Benzene is a myclotoxicant known to suppress bone marrow cell proliferation and to induce hematologic disorders in humans and animals.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ The Erexson data(57> are the lowest concentrations of inhaled benzene that have been reported to induce genotoxicity.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ Benzene is classified as a human carcinogen by American Conference of Governmental Industrial Hygienists (ACGIH) and International Agency for Research on Cancer (IARC).
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

.The chemical industry claims it wasn't until 1979 that the cancer-inducing properties were determined "conclusively" in humans, despite many references to this fact in the medical literature.^ In view of the fact that benzene readily ingresses into the atmosphere on account of its physical properties, it can be transported over long distances despite relatively short transformation reactions.
  • Benzene 10 February 2010 12:012 UTC www2.gtz.de [Source type: Academic]

.Industry exploited this "discrepancy" and tried to discredit animal studies which showed benzene caused cancer, saying that they weren't relevant to humans.^ Benzene exposure can cause chromosomal aberrations in animals and humans.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ Benzene is a myclotoxicant known to suppress bone marrow cell proliferation and to induce hematologic disorders in humans and animals.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ Despite its sweet smell and colorless appearance, benzene is known to cause leukemia (bone marrow cancer) with chronic exposure, as well as anemia and immune deficiency.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

.Benzene has been shown to cause cancer in both sexes of multiple species of laboratory animals exposed via various routes.^ Despite its sweet smell and colorless appearance, benzene is known to cause leukemia (bone marrow cancer) with chronic exposure, as well as anemia and immune deficiency.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Animal experiments exposing pregnant mice and rats to inhaled benzene in general demonstrated increased fetal skeletal variants and reduced fetal weight, but failed to demonstrate consistent convincing evidence of teratogenecity.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Benzene exposure can cause chromosomal aberrations in animals and humans.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

[20][21]
.Some women who breathed high levels of benzene for many months had irregular menstrual periods and a decrease in the size of their ovaries.^ VERDICT Exposure to high concentration of the chemical Benzene in the workplace - temporary breathing and equilibrium problems and severe migraine headaches continuing intermittently -inability to continue work.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Repeated exposure to high levels of benzene (≤200 ppm) can result in persistent CNS effects.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ OSHA mandates that acutely exposed workers who have urinary phenol levels above 75 mg/L receive periodic CBCs (at least monthly for 3 months) to monitor potential bone marrow effects.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

.It is not known whether benzene exposure affects the developing fetus in pregnant women or fertility in men.^ However, effects of benzene exposure in pregnant women is not well understood.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Despite its sweet smell and colorless appearance, benzene is known to cause leukemia (bone marrow cancer) with chronic exposure, as well as anemia and immune deficiency.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Chronic exposure of 1 to 25 years at benzene concentrations of 75 ppm has been associated with the development of anemia and leukopenia (Kipen et al., 1989).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Animal studies have shown low birth weights, delayed bone formation, and bone marrow damage when pregnant animals breathed benzene.^ Benzene is a myclotoxicant known to suppress bone marrow cell proliferation and to induce hematologic disorders in humans and animals.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ Despite its sweet smell and colorless appearance, benzene is known to cause leukemia (bone marrow cancer) with chronic exposure, as well as anemia and immune deficiency.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Animal experiments exposing pregnant mice and rats to inhaled benzene in general demonstrated increased fetal skeletal variants and reduced fetal weight, but failed to demonstrate consistent convincing evidence of teratogenecity.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Benzene has been connected to a rare form of kidney cancer in two separate studies, one involving tank truck drivers, and the other involving seamen on tanker vessels, both carrying benzene-laden chemicals.^ Usage: In the chemical industry pure benzene forms the most important basis for aromatic intermediate products as well as for the group of cycloaliphatic compounds.
  • Benzene 10 February 2010 12:012 UTC www2.gtz.de [Source type: Academic]

^ Wong O (1987) An industry wide mortality study of chemical workers occupationally exposed to benzene.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Chronic benzene exposure has also been associated with lung cancer in epidemiological studies.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

.The US Department of Health and Human Services (DHHS) classifies benzene as a human carcinogen.^ Benzene is a human and rodent clastogen and carcinogen.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ The Department of Health and Human Services has determined that benzene is a known human carcinogen.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ The rodent carcinogenicity data support the designation of benzene as a known human carcinogen.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

.Long-term exposure to excessive levels of benzene in the air causes leukemia, a potentially fatal cancer of the blood-forming organs, in susceptible individuals.^ Repeated exposure to benzene may cause a blood disorder (i.e., aplastic anemia and pancytopenia) and cancer of blood-forming cells (i.e., leukemia).
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ Even short-term exposure can cause headaches, dizziness, confusion and sometimes death when benzene is breathed or ingested.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Despite its sweet smell and colorless appearance, benzene is known to cause leukemia (bone marrow cancer) with chronic exposure, as well as anemia and immune deficiency.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

.In particular, Acute myeloid leukemia or acute non-lymphocytic leukaemia (AML & ANLL) is not disputed to be caused by benzene.^ Despite its sweet smell and colorless appearance, benzene is known to cause leukemia (bone marrow cancer) with chronic exposure, as well as anemia and immune deficiency.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Haematological abnormalities, especially anemia, leukopenia, thrombocytopenia, pancytopenia, or acute myelogenous leukemia, associated with chronic use of benzene suggest benzene poisoning.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Chronic benzene exposure in the workplace has been associated with hematologic disorders (i.e., thrombocytopenia, aplastic anemia, pancytopenia, and acute myelgenous leukemia).
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

.Several tests can determine exposure to benzene.^ VERDICT Exposure to high concentration of the chemical Benzene in the workplace - temporary breathing and equilibrium problems and severe migraine headaches continuing intermittently -inability to continue work.
  • Benzene - Attorney, Lawsuit, Law Suit, Case, Claim, Settlement, Lawyer, Litigation 10 February 2010 12:012 UTC benzene.legalview.info [Source type: General]

^ Additional tests for patients who have substantial benzene exposure include ECG monitoring, urinalysis, determinations of BUN, creatinine, and liver function test.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ However, benzene exposure ha5 failed consistently to induce point mutations, in genotoxicity test systems.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

.There is a test for measuring benzene in the breath; this test must be done shortly after exposure.^ The benzene concentration in the tank vapor space increased to a measured peak of 60 parts per million (ppm) during the first pump run test.
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ For oral exposures, gastric aspiration may be helpful for ingestion of large quantities of benzene, although there is a risk of pulmonary aspiration.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ There are reports of retrobulbar neuritis or optic neuritis occurring after inhalation exposure to benzene (Grant & Schuman, 1993).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Benzene can also be measured in the blood; however, because benzene disappears rapidly from the blood, measurements are accurate only for extremely recent exposures.^ Phenol, muconic acid or S-phenyl-N-acetyl cysteine (PhAC), breakdown products of benzene, can be measured in urine to prove benzene exposure.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ Sherwood RJ & Carter FWG (1970) The measurement of occupational exposure to benzene vapour.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ In order to detect the haematological effects of chronic benzene exposure, it is recommended to follow blood counts at regular intervals.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Benzene exposure should always be minimized.^ Patients who have histories or evidence of substantial exposure and all persons who have ingested benzene should be transported to a medical facility for evaluation.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ Otherwise appropriate respiratory protection should be worn at benzene concentrations above occupational exposure limits.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

In the body, benzene is metabolized. .Certain metabolites, such as trans,trans-muconic acid can be measured in the urine.^ Phenol, muconic acid or S-phenyl-N-acetyl cysteine (PhAC), breakdown products of benzene, can be measured in urine to prove benzene exposure.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

.However, this test must be done shortly after exposure and is not a reliable indicator of benzene exposure, since the same metabolites may be present in urine from other sources.^ Other urinary metabolites of benzene can also be used to document exposure.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ Management discussion Since the treatment of acute exposure to benzene is limited to decontamination and supportive care, there are few controversies over treatment other than the usual discussion about the risks and benefits of lavage and/or activated charcoal.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Benzene may also be detected in blood for a short period of time after exposure, and it may be measured in exhaled breath.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.The United States Environmental Protection Agency has set the maximum permissible level of benzene in drinking water at 0.005 milligrams per liter (0.005 mg/L).^ Low humidity The ability of a SKC 575-002 Passive Sampler to collect benzene from a relatively dry atmosphere was tested by sampling an atmosphere containing 73.4 mg/m of benzene at an absolute humidity of 1.9 milligrams of water per liter of air (about 10% relative humidity at 22.2C).
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ Low concentration The ability of 3M 3520 OVMs to collect benzene at low concentrations was determined by sampling a test atmosphere containing 0.1 times the target concentration of benzene and having an absolute humidity of 15.7 milligrams of water per liter of air (about 80% relative humidity at 22.2C).
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ Section 4.9.2 ) Low humidity The ability of a SKC 575-002 Passive Sampler to collect benzene from a relatively dry atmosphere was determined by sampling an atmosphere of two times the target concentration of benzene and having an absolute humidity of 1.9 milligrams of water per liter of air (about 10% relative humidity at 22.2C).
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

The EPA requires that spills or accidental releases into the environment of 10 pounds (4.5 kg) or more of benzene be reported to the EPA.
.The U.S. Occupational Safety and Health Administration (OSHA) has set a permissible exposure limit of 1 part of benzene per million parts of air (1 ppm) in the workplace during an 8-hour workday, 40-hour workweek.^ Occupational Safety and Health Administration: 29 CFR Pan 1910, Occupational Exposure to Benzene; Final Rule.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ OSHA PEL (permissible exposure limit) = 1 ppm (averaged over an 8-hour workshift).
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

^ The National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit (REL) is 0.1 ppm (NIOSH, 1990).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.The short term exposure limit for airborne benzene is 5 ppm for 15 minutes.^ Wash-out effects merely result in short-term extraction from the atmosphere since benzene readily evaporates again from the surface of water or soil.
  • Benzene 10 February 2010 12:012 UTC www2.gtz.de [Source type: Academic]

^ Chronic exposure of 1 to 25 years at benzene concentrations of 75 ppm has been associated with the development of anemia and leukopenia (Kipen et al., 1989).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Sherwood RJ (1988) Pharmacokinetics of benzene in a human after exposure at about the occupational limit.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.In recent history there have been many examples of the harmful health effects of benzene and its derivatives.^ Hudak A & Ungvary G (1978) Embryotoxic effects of benzene and its methyl derivatives: toluene, xylene.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Benzene was previously used widely as a solvent, but this use has decreased in many countries due to the concern over carcinogenic effects.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Haley TJ (1977) Evaluation of the health effects of benzene inhalation.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

Toxic Oil Syndrome caused localised immune-suppression in Madrid in 1981 from people ingesting anilide-contaminated rapeseed oil. .Chronic Fatigue Syndrome has also been correlated with people who eat "denatured" food that use solvents to remove fat or contain benzoic acid but causality is unproven.^ Although in the United States benzene has been removed from commercial solvents, the use of industrial solvents may still be a source of exposure.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

[citation needed]
.Workers in various industries that make or use benzene may be at risk for being exposed to high levels of this carcinogenic chemical.^ USES 4.1 Uses 4.1.1 Uses 4.1.2 Description Benzene is used as an intermediate in the manufacture of a number of chemicals, including ethylbenzene (used in the synthesis of styrene), cumene (used in the synthesis of phenol and for the manufacture of phenolic resins and nylon intermediates), cyclohexane (used to make nylon resins), and nitrobenzene (used in the synthesis of aniline).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ An increased frequency of chromatid and isochromatid breaks was found in children of women exposed during pregnancy to a mix of benzene and other solvents in the printing industry and chemical laboratories (Funes-Cravioto et al., 1977).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Industries that involve the use of benzene include the rubber industry, oil refineries, chemical plants, shoe manufacturers, and gasoline-related industries.^ USES 4.1 Uses 4.1.1 Uses 4.1.2 Description Benzene is used as an intermediate in the manufacture of a number of chemicals, including ethylbenzene (used in the synthesis of styrene), cumene (used in the synthesis of phenol and for the manufacture of phenolic resins and nylon intermediates), cyclohexane (used to make nylon resins), and nitrobenzene (used in the synthesis of aniline).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Occupationally exposed populations Individuals working in industries involved with benzene production (petrochemical industry, coke manufacturing), rubber tire or cast rubber film manufacturing, transport or storage of benzene or benzene-containing products, and gas station employees all are at risk for excess benzene exposure (ATSDR, 1993).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Wong O (1987) An industry wide mortality study of chemical workers occupationally exposed to benzene.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.In 1987, OSHA estimated that about 237,000 workers in the United States were potentially exposed to benzene, but it is not known if this number has substantially changed since then.^ The Occupational Safety and Health Administration (OSHA) recommends monthly blood counts and removal from areas with high benzene exposure for white blood cell counts below 4,000/mm 3 or erythrocyte counts below 4,000,000/mm 3 (OSHA, 1987).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Ott MG, Townsend JC, Fishbeck WA, Langner RA (1978) Mortality among workers occupationally exposed to benzene.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Aksoy M, Erdem S & Dincol G (1974) Leukemia in shoe-workers exposed chronically to benzene.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Water and soil contamination are important pathways of concern for transmission of benzene contact.^ Benzene may also be a contaminant in drinking water (ATSDR, 1993).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.In the U.S. alone there are approximately 100,000 different sites which have benzene soil or groundwater contamination.^ Approximately 9,600 kilograms of excess sodium tetraphenylborate in 170,000 gallons of solution decomposed at an unexpectedly rapid rate, generating benzene.
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ There are different values given, depending on whether both, either, or neither temperature ( T ) or atmospheric pressure ( P ) are known at the sampling site.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ An incubation period of approximately 100 hours was observed before the decomposition reaction proceeded; a maximum rate of 2,000,000 µg/liter-hr was observed.
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

.In 2005, the water supply to the city of Harbin in China with a population of almost nine million people, was cut off because of a major benzene exposure.^ Major Uses and Sources of ®ccupational Exposure At one time, benzene was an important solvent.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ Because the benzene has a higher molecular weight compared to air (78 versus 29) or water vapor (18), .
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ In the United States, smoking accounts for approximately half of the total population exposure to benzene (Wallace, 1989).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Benzene leaked into the Songhua River, which supplies drinking water to the city, after an explosion at a China National Petroleum Corporation (CNPC) factory in the city of Jilin on 13 November.^ Benzene may also be a contaminant in drinking water (ATSDR, 1993).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

In March 2006, the official Food Standards Agency in Britain conducted a survey of 150 brands of soft drinks. .It found that four contained benzene levels above World Health Organization limits.^ M 3520 OVMs Extraction efficiency The extraction efficiencies of benzene were determined by liquid-spiking four 3M 3520 OVMs, at each concentration level, with the analyte at the RQL to 2 times the target concentration.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ Charcoal tubes Extraction efficiency The extraction efficiencies of benzene were determined by liquid-spiking four charcoal tubes, at each concentration level, with the analyte from the RQL to 2 times the target concentration.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ At an exposure level of 25 ppm of benzene in a sedentary individual, exhaled breath was found to contain 2 ppm of benzene at the end of a 4.5 hour exposure and 0.2 ppm 16 hours later (Sherwood & Carter, 1970).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

The affected batches were removed from sale.[22] (See also benzene in soft drinks).

Molecular toxicology

.The paradigm of toxicological assessment of benzene is slowly shifting towards the domain of molecular toxicology as it allows understanding of fundamental biological mechanisms in a better way.^ Effort is currently being made toward understanding the mechanisms and kinetics of benzene retention and release.
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ The goal of the various experimental programs was to characterize the mechanism of benzene generation by understanding its phenomenology, stoichiometry, reaction mechanisms, and kinetics.
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ This section reviews the potential mechanisms for benzene retention and release, and considers the safety implications of a limited understanding of those mechanisms.
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

.Glutathione seems to play an important role by protecting against benzene induced DNA breaks and it is being identified as a new biomarker for exposure and effect[23].^ Summary of clinical effects Acute neurological toxicity from benzene exposure may cause headache, dizziness, drowsiness, confusion, tremors, and loss of consciousness.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ After exposure to 63 to 405 mg/m 3 of benzene for 1 to 5 hours, 51 to 87% was excreted in the urine as phenol over a period of 23 to 50 hours (Hunter & Blair, 1972).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Ikeda M & Ohtsuji H (1971) Phenobarbital-induced protection against toxicity of toluene and benzene in the rat.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Benzene causes chromosomal aberrations in the peripheral blood leukocytes and bone marrow explaining the higher incidence of leukemia and multiple myeloma caused by chronic exposure.^ Benzene exposure can cause chromosomal aberrations in animals and humans.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ Chronic benzene exposure is associated with an increased risk of leukemia.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Benzene is a myclotoxicant known to suppress bone marrow cell proliferation and to induce hematologic disorders in humans and animals.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

.These aberrations can be monitored using fluorescent in situ hybridization (FISH) with DNA probes to assess the effects of benzene along with the hematological tests as markers of hematotoxicity[24].^ This modification is essentially an adaptation of sampling probes and gas chromatograph analysis capability used in the depletion of the benzene inventory in Tank 48.
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ M 3520 OVMs Storage samples for benzene were prepared by collecting samples from a controlled test atmosphere using the recommended sampling conditions.
  • Sampling and Analytical Methods: Benzene, 1005 10 February 2010 12:012 UTC www.osha.gov [Source type: Academic]

^ Measurement of exhaled benzene has been used to monitor exposure, but is affected by smoking (Brugnone et al., 1989).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Benzene metabolism involves enzymes coded for by polymorphic genes.^ Nakajima T, Okino T, Sato A (1987) Kinetic studies on benzene metabolism in rat liver-possible presence of three forms of benzene metabolizing enzymes in the liver.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Pawar SS & Mungikar AM (1975) Changes in the activities of hepatic drug metabolizing enzymes and lipid peroxidation caused by benzene and toluene.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Studies have shown that genotype at these loci may influence susceptibility to the toxic effects of benzene exposure.^ For oral exposures, gastric aspiration may be helpful for ingestion of large quantities of benzene, although there is a risk of pulmonary aspiration.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ However, there are a multitude of studies on the haematological effects of intermediate and chronic exposure, which include aplastic anaemia, pancytopenia, and varying degrees of thrombocytopenia and leukopenia mediated through bone marrow toxicity.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Additional information on hematological effects of benzene exposure is included under sections 7.3 and 7.5.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

Individuals carrying variant of NAD(P)H:quinone oxidoreductase 1 (NQO1), microsomal epoxide hydrolase (EPHX) and deletion of the glutathione S-transferase T1 (GSTT1) showed a greater frequency of DNA single-stranded breaks.[25]

Summary

.According to the Agency for Toxic Substances and Disease Registry (ATSDR) (2007), benzene is both an anthropogenically produced and naturally occurring chemical from processes that include: volcanic eruptions, wild fires, synthesis of chemicals such as phenol, production of synthetic fibers and fabrication of rubbers, lubricants, pesticides, medications, and dyes.^ PHYSICO-CHEMICAL PROPERTIES 3.1 Origin of the substance Benzene occurs naturally but is primarily produced from petroleum products (ATSDR, 1993).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ At present, such uses are minimal; most benzene is consumed in the chemical industry as a raw material for numerous organic chemicals and in plastics manufacture.
  • Notice of Intended Changes - Benzene 10 February 2010 12:012 UTC tobaccodocuments.org [Source type: Academic]

^ USES 4.1 Uses 4.1.1 Uses 4.1.2 Description Benzene is used as an intermediate in the manufacture of a number of chemicals, including ethylbenzene (used in the synthesis of styrene), cumene (used in the synthesis of phenol and for the manufacture of phenolic resins and nylon intermediates), cyclohexane (used to make nylon resins), and nitrobenzene (used in the synthesis of aniline).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.The most common route of benzene exposure is through inhalation of air emissions from tobacco smoke and motor vehicle exhaust; however, ingestion and dermal absorption of benzene can also occur through contact with contaminated water.^ Absorption by route of exposure .
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ High risk circumstances of poisoning The most common form of exposure to benzene is occupational, and both occupational and environmental exposures to benzene are overwhelmingly through inhalation.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ For a worker exposed to 10 ppm of ambient benzene with his entire skin exposed, and 100 cm2 of skin exposed directly to 5% benzene (gasoline), the expected hourly absorption of benzene will be 7.5 L from inhalation, 1.5 L from ambient skin absorption, and 7.0 L from direct skin contact with the liquid (Blank & McAuliffe, 1985).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Benzene is hepatically metabolized and excreted in the urine.^ Metabolism Benzene is both exhaled unchanged in the lungs and excreted as metabolites in the urine.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ After exposure to 63 to 405 mg/m 3 of benzene for 1 to 5 hours, 51 to 87% was excreted in the urine as phenol over a period of 23 to 50 hours (Hunter & Blair, 1972).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Pawar SS & Mungikar AM (1975) Changes in the activities of hepatic drug metabolizing enzymes and lipid peroxidation caused by benzene and toluene.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Measurement of air and water levels of benzene is accomplished through collection via activated charcoal tubes, which are then analyzed with a gas chromatograph.^ This modification is essentially an adaptation of sampling probes and gas chromatograph analysis capability used in the depletion of the benzene inventory in Tank 48.
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ Breath samples for benzene are collected in standard breath sampling tubes on a solid sorbent such as activated charcoal, silica gel, or Tenax GC (ATSDR, 1993).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ Catechol is produced via this pathway through the intermediate benzene glycol, and is excreted as a glucuronide or sulfate conjugate (Henderson et al., 1989).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.The measurement of benzene in humans can be accomplished via urine, blood, and breath tests; however, all of these have their limitations because benzene is rapidly metabolized in the human body into by-products called metabolites.^ Morimoto K, Wolff S, Koizumi A (1983) Induction of sister-chromatid exchanges in human lymphocytes by microsomal activation of benzene metabolites.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ The benzene concentration in the tank vapor space increased to a measured peak of 60 parts per million (ppm) during the first pump run test.
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ Sherwood RJ (1988) Pharmacokinetics of benzene in a human after exposure at about the occupational limit.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

[26]

Biological oxidation and carcinogenic activity

.One way of understanding the carcinogenic effects of benzene is by examining the products of biological oxidation.^ This laboratory test of different batch compositions could be implemented in the short term until a fuller understanding of the effect of slurry composition on benzene generation rate is achieved.
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

^ Benzene was previously used widely as a solvent, but this use has decreased in many countries due to the concern over carcinogenic effects.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

.Pure benzene, for example, oxidizes in the body to produce an epoxide, benzene oxide, which is not excreted readily and can interact with DNA to produce harmful mutations.^ Catechol is produced via this pathway through the intermediate benzene glycol, and is excreted as a glucuronide or sulfate conjugate (Henderson et al., 1989).
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

^ The first step in benzene metabolism is the formation of benzene oxide, an epoxide, by cytochrome P-450 dependent mixed function oxidases.
  • Benzene (PIM 063) 10 February 2010 12:012 UTC www.inchem.org [Source type: Academic]

See also

References

  1. ^ David R. Lide, ed.. ""Physical Constants of Organic Compounds", in CRC Handbook of Chemistry and Physics, Internet Version 2005, <http://www.hbcpnetbase.com>". CRC Press. 
  2. ^ a b A. J. Rocke (1985). "Hypothesis and Experiment in the Early Development of Kekule's Benzene Theory". Annals of Science 42: 355–81. doi:10.1080/00033798500200411. 
  3. ^ M. Faraday (1825). "On New Compounds of Carbon and Hydrogen, and on Certain Other Products Obtained during the Decomposition of Oil by Heat". Philosophical Transactions of the Royal Society of London 115: 440–466. doi:10.1098/rstl.1825.0022. http://links.jstor.org/sici?sici=0261-0523%281825%29115%3C440%3AONCOCA%3E2.0.CO%3B2-B. 
  4. ^ R. Kaiser (1968). "Bicarburet of Hydrogen. Reappraisal of the Discovery of Benzene in 1825 with the Analytical Methods of 1968". Angewandte Chemie International Edition in English 7 (5): 345–350. doi:10.1002/anie.196803451. 
  5. ^ E. Mitscherlich (1834). "Ueber das Benzol und die Säuren der Oel- und Talgarten". Annalen der Pharmacie 9 (1): 39–48. doi:10.1002/jlac.18340090103. 
  6. ^ F. A. Kekulé (1865). "Sur la constitution des substances aromatiques". Bulletin de la Societe Chimique de Paris 3: 98–110. 
  7. ^ F. A. Kekulé (1866). "Untersuchungen uber aromatische Verbindungen". Liebigs Annalen der Chemie 137: 129–36. doi:10.1002/jlac.18661370202. 
  8. ^ Translated into English by D. Wilcox and F. Greenbaum, Journal of Chemical Education, 42 (1965), 266–67.
  9. ^ F. A. Kekulé (1890). "Benzolfest: Rede". Berichte der Deutschen Chemischen Gesellschaft 23: 1302–11. doi:10.1002/cber.189002301204. http://gallica.bnf.fr/ark:/12148/bpt6k90720c/f1304.chemindefer. 
  10. ^ O. T. Benfey, "August Kekulé and the Birth of the Structural Theory of Organic Chemistry in 1858," Journal of Chemical Education, 35 (1958), 21–23
  11. ^ Jean Gillis, "Auguste Kekulé et son oeuvre, realisee a Gand de 1858 a 1867," Memoires de l'Academie Royale de Belgique, 37:1 (1866), 1–40.
  12. ^ K. Lonsdale (1929). "The Structure of the Benzene Ring in Hexamethylbenzene". Proceedings of the Royal Society 123A: 494. 
  13. ^ K. Lonsdale (1931). "An X-Ray Analysis of the Structure of Hexachlorobenzene, Using the Fourier Method". Proceedings of the Royal Society 133A: 536–553. http://gallica.bnf.fr/ark:/12148/bpt6k56226p/f558.table. 
  14. ^ bonding in benzene - the Kekulé structure
  15. ^ "Unicode Character 'BENZENE RING' (U+232C)". http://www.fileformat.info/info/unicode/char/232c/index.htm. Retrieved 2009-01-16. 
  16. ^ "Unicode Character 'BENZENE RING WITH CIRCLE' (U+23E3)". http://www.fileformat.info/info/unicode/char/23e3/index.htm. Retrieved 2009-01-16. 
  17. ^ Kolmetz, Gentry, Guidelines for BTX Revamps, AIChE 2007 Spring Conference
  18. ^ [http://www.epa.gov/EPA-AIR/2006/March/Day-29/a2315b.htm "Control of Hazardous Air Pollutants From Mobile Sources"]. U.S. Environmental Protection Agency. 2006-03-29. pp. 15853. http://www.epa.gov/EPA-AIR/2006/March/Day-29/a2315b.htm. Retrieved 2008-06-27. 
  19. ^ ToxFAQs for Benzene, Agency for Toxic Substances and Disease Registry, Department of Health and Human Services
  20. ^ Huff J (Apr-Jun 2007). "Benzene-induced cancers: abridged history and occupational health impact". Int J Occup Environ Health 13 (2): 213–21. PMID 17718179. 
  21. ^ Rana SV; Verma Y (April 2005). "Biochemical toxicity of benzene". J Environ Biol 26 (2): 157–68. PMID 16161967. 
  22. ^ "FDA: Too Much Benzene In Some Drinks", CBS News, May 19, 2006, retrieved July 11, 2006
  23. ^ Fracasso, M.E. (2009). "Low air levels of benzene: Correlation between biomarkers of exposure and genotoxic effects". Toxicol Lett [Epub ahead of print] (May 7). }
  24. ^ *Eastmond, D.A. (2000). "Detection of hyperdiploidy and chromosome breakage in interphase human lymphocytes following exposure to the benzene metabolite hydroquinone using multicolor fluorescence in situ hybridization with DNA probes". Mutat Res 322 (1): pp. 9–20. }
  25. ^ *Garte, S (2000). "Genetic susceptibility to benzene toxicity in humans". J Toxicol Environ Health A 71 (22): pp. 1482–1489. }
  26. ^ Agency for Toxic Substances and Disease Registry. (2007). Benzene: Patient information sheet.

External links

.

1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

.BENZENE, C 6 H 6, a hydrocarbon discovered in 1825 by Faraday in the liquid produced in the compression of the illuminating gas obtained by distilling certain oils and fats.^ Benzene was first discovered by the English scientist Michael Faraday in 1825 in illuminating gas.
  • benzene (C6H6) (chemical compound) -- Britannica Online Encyclopedia 10 February 2010 12:012 UTC www.britannica.com [Source type: Reference]

^ The famous chemist, Michael Faraday discovered benzene in 1825 while distilling crude oil.
  • The Chemistry of Benzene: A Hexagonal Molecule on which is Founded Aromatic Chemistry 10 February 2010 12:012 UTC organic-chemistry.suite101.com [Source type: FILTERED WITH BAYES]

^ By 1833, it was discovered that benzene can be produced when gum benzoin and lime are distilled.
  • What is Benzene - Benzene Exposure, Benzene Leukemia and Benzene Lawyers 10 February 2010 12:012 UTC www.benzenelawyer.net [Source type: Reference]

.E. Mitscherlich prepared it in 1834 by distilling benzoic acid with lime; and in 1845 Hofmann discovered it in coal-tar.^ Mitscherlich obtained it from a distillation of benzoic acid, obtained from benzoin (q.v.
  • Benzene Definition | Definition of Benzene at Dictionary.com 10 February 2010 12:012 UTC dictionary.reference.com [Source type: Reference]

^ E. Mitscherlich prepared it in 1834 by distilling benzoic acid with lime ; and in 1845 Hofmann discovered it in coal-tar .

^ In 1834 German chemist Eilhardt Mitscherlich heated benzoic acid with lime and produced benzene.
  • benzene (C6H6) (chemical compound) -- Britannica Online Encyclopedia 10 February 2010 12:012 UTC www.britannica.com [Source type: Reference]

.It was named " benzin " or " benzine " by Mitscherlich in 1833, but in the following year Liebig proposed " benzol " (the termination of being suggested by the Lat.^ It was named " benzin " or " benzine " by Mitscherlich in 1833, but in the following year Liebig proposed " benzol " (the termination of being suggested by the Lat.

^ The process originally suggested by Mansfield is generally followed, the success of the operation being principally conditioned by the efficiency of the dephlegmator, in which various improvements have been made.

^ Mitscherlich named this substance benzin , which became benzene when translated into English.

.oleum, oil); the form " benzene " was due to A. W.EHof mann.^ BENZENE FACTS * Michael Faraday discovered benzene in 1825 when he isolated it from oil gas to form a chemical, six parts carbon, six parts hydrogen .
  • Soft Drinks Found to Contain High Levels of Cancer-Causing Benzene 10 February 2010 12:012 UTC www.organicconsumers.org [Source type: FILTERED WITH BAYES]

^ Benzene lawsuits have been most prevalent in California and Texas, in part due to the large oil and rubber industries in both states.
  • Benzene Lawsuit by AttorneyOne.com 10 February 2010 12:012 UTC www.attorneyone.com [Source type: FILTERED WITH BAYES]

^ Benzene is a colorless, sweet smelling and flammable chemical that is processed from crude oil that forms toxic vapors and is associated with many health disorders.
  • Benzene Leukemia by AttorneyOne.com 10 February 2010 12:012 UTC www.attorneyone.com [Source type: FILTERED WITH BAYES]

The word " benzine " is sometimes used in commerce for the coal-tar product, but also for the light petroleum better known as petroleum-benzine; a similar ambiguity is presented by the word " benzoline," which is applied to the same substances as the word " benzine." " Benzene " is the term used by English chemists, " benzol " is used in Germany, and " benzole " in France.
.Benzene is manufactured from the low-boiling fractions of the coal-tar distillate '(see' Coal-Tar).^ Benzene is manufactured from the low-boiling fractions of the coal-tar distillate '( see' Coal-Tar ).

^ It is derived from toluene (hydrocarbon derived from petroleum ) or fractional distillation of coal tar .

^ These industries include benzene production (petrochemicals, petroleum refining and coke and coal chemical manufacturing), rubber tire manufacturing and storage or transport of benzene and petroleum products containing benzene.
  • Benzene Lawsuits - AML Leukemia Lawsuit, Acute Myelogenous Leukemia from Benzene Exposure (Texas Lawyer and Attorney) 10 February 2010 12:012 UTC www.benzenelawsuits.com [Source type: FILTERED WITH BAYES]

.The first successful fractionation of coal-tar naphtha was devised by C. B. Mansfield (1819-1855), who separated a benzol distilling below too from a less volatile naphtha by using a simple dephlegmator.^ The first successful fractionation of coal-tar naphtha was devised by C. B. Mansfield (1819-1855), who separated a benzol distilling below too from a less volatile naphtha by using a simple dephlegmator.

^ At first, the oil was manufactured principally for combustion in the Read-Holliday lamp and for dissolving rubber , but the development of the coal-tar colour industry occasioned a demand for benzols of definite purity.

^ C 6 H 6 , obtained chiefly from coal tar: used in the manufacture of commercial and medicinal chemicals, dyes, and as a solvent for resins, fats, or the like.

.At first, the oil was manufactured principally for combustion in the Read-Holliday lamp and for dissolving rubber, but the development of the coal-tar colour industry occasioned a demand for benzols of definite purity.^ At first, the oil was manufactured principally for combustion in the Read-Holliday lamp and for dissolving rubber , but the development of the coal-tar colour industry occasioned a demand for benzols of definite purity.

^ "The major uses of benzene include the manufacturing of industrial chemicals (e.g., polymers, detergents, pesticides, dyes, plastics, resins) and explosives, and as a solvent for waxes, resins, oils, and natural rubber, among other materials.
  • Benzene, Aplastic Anemia, and Leukemia 10 February 2010 12:012 UTC www.haz-map.com [Source type: Academic]

^ Benzene (C.A.S. 71-43-2) is produced naturally by volcanoes and forest fires, and is present in many plants and animals, but is also a major industrial chemical made from coal and oil.
  • Environment Writer Chemical Backgrounder Benzene 10 February 2010 12:012 UTC www.environmentwriter.org [Source type: Academic]

In the earlier stages 30%, 50% and go % benzols were required, the 30% being mainly used for the manufacture of "aniline for red," and the 90% for "aniline for blue." (The term " 30% benzol " means that 30% by volume distils below ioo°.) .A purer benzol was subsequently required for the manufacture of aniline black and other dye-stuffs.^ A purer benzol was subsequently required for the manufacture of aniline black and other dye-stuffs.

^ In the earlier stages 30%, 50% and go % benzols were required, the 30% being mainly used for the manufacture of " aniline for red," and the 90% for "aniline for blue."

^ Benzene is used in the manufacture of rubber, plastics, various synthetic fibers including nylon, lubricants, drugs, dyes, detergents, pesticides, and other chemicals.
  • Benzene Attorney Personal Injury Lawyer | Accident Attorneys | Ferrer, Poirot & Wansbrough Attorney at Law 10 February 2010 12:012 UTC www.lawyerworks.com [Source type: FILTERED WITH BAYES]
  • Exposure To Benzene | Norris Injury Lawyers | Benzene Lawyer Birmingham Huntsville Gadsden Anniston Tuscaloosa Montgomery Mobile 10 February 2010 12:012 UTC www.norrisinjurylawyers.com [Source type: FILTERED WITH BAYES]

.The process originally suggested by Mansfield is generally followed, the success of the operation being principally conditioned by the efficiency of the dephlegmator, in which various improvements have been made.^ The process originally suggested by Mansfield is generally followed, the success of the operation being principally conditioned by the efficiency of the dephlegmator, in which various improvements have been made.

^ It was named " benzin " or " benzine " by Mitscherlich in 1833, but in the following year Liebig proposed " benzol " (the termination of being suggested by the Lat.

^ Following completion of the inerting tests, Westinghouse Savannah River Company planned to begin near-term operation of the In-Tank Precipitation Facility for process verification testing.
  • DNFSB/TECH-14 10 February 2010 12:012 UTC www.dnfsb.gov [Source type: Academic]

.The light oil fraction of the coal-tar distillate, which comes over below 140° and consists principally of benzene, toluene and the xylenes, yields on fractionation (i) various volatile impurities such as carbon disulphide, (2) the benzene fraction boiling at about 80° C., (3) the toluene fraction boiling at too°, (4) the xylene fraction boiling at 140°.^ It comes from light coal tar oil and chemically is C6H6.
  • Benzene definition - Medical Dictionary definitions of popular medical terms easily defined on MedTerms 10 February 2010 12:012 UTC www.medterms.com [Source type: FILTERED WITH BAYES]

^ It is derived from toluene (hydrocarbon derived from petroleum ) or fractional distillation of coal tar .

^ Benzene is manufactured from the low-boiling fractions of the coal-tar distillate '( see' Coal-Tar ).

.The fractions are agitated with strong sulphuric acid, and then washed with a caustic soda solution.^ The fractions are agitated with strong sulphuric acid , and then washed with a caustic soda solution.

^ The toluene fraction requires a more thorough washing with sulphuric acid in order to eliminate the thiotolene, which is sulphonated much less readily than thiophene.

^ Similar Be produced by rectifying the naphthalene fraction obtained from distilling coal tar, after acid wash....
  • Benzene & Derivatives - Benzene & Derivatives and more 10 February 2010 12:012 UTC www.alibaba.com [Source type: General]

.The washed products are then refractionated.^ The washed products are then refractionated.

.The toluene fraction requires a more thorough washing with sulphuric acid in order to eliminate the thiotolene, which is sulphonated much less readily than thiophene.^ The toluene fraction requires a more thorough washing with sulphuric acid in order to eliminate the thiotolene, which is sulphonated much less readily than thiophene.

^ Sulphuric acid gives a benzene sulphonic acid.

^ Individuals with exposures from less than five years to more than 30 years have developed, and died from, leukemia.
  • Dr. Thrasher Resume 10 February 2010 12:012 UTC www.drthrasher.org [Source type: Academic]

.Benzene is a colourless, limpid, highly refracting liquid, having a pleasing and characteristic odour.^ Benzene is a colourless liquid with a sweet odour.

^ Benzene is a clear, colourless liquid with a characteristic, aromatic hydrocarbon odour.
  • OSH Answers: 1-Basic Information on Benzene 10 February 2010 12:012 UTC gala.ccohs.ca [Source type: Reference]

^ Benzene is a highly volatile, flammable liquid.
  • ATSDR - MMG: Benzene 10 February 2010 12:012 UTC www.atsdr.cdc.gov [Source type: Academic]

.It may be solidified to rhombic crystals which melt at 5.4° C. (Mansfield obtained perfectly pure benzene by freezing a carefully fractionated sample.^ It may be solidified to rhombic crystals which melt at 5.4° C. (Mansfield obtained perfectly pure benzene by freezing a carefully fractionated sample.

^ Reliance's Benzene at the Hazira plant is manufactured by the sulpholane extraction process of the Pyrolysis Gasoline fraction obtained from Naphtha cracker.
  • Benzene :: Reliance Industries Limited. 10 February 2010 12:012 UTC www.ril.com [Source type: FILTERED WITH BAYES]

^ If you have a BMF disease, and have been exposed to benzene, you may be able to obtain compensation for your injuries, so contact a benzene lawyer today.

) .It boils at 80 4°, and the vapour is highly inflammable, the flame being extremely smoky.^ It boils at 80 4°, and the vapour is highly inflammable, the flame being extremely smoky.

^ Benzene and its homologues are highly inflammable liquids and burn with a sooty flame.
  • Properties of Benzene | TutorVista 10 February 2010 12:012 UTC www.tutorvista.com [Source type: Academic]

.Its specific gravity is o 899 at o° C. It is very slightly soluble in water, more soluble in alcohol, and completely miscible with ether, acetic acid and carbon disulphide.^ It is slightly soluble in water and is miscible with alcohol, ether, acetone, carbon tetrachloride, carbon disulfide, and glacial acetic acid.
  • Environment Writer Chemical Backgrounder Benzene 10 February 2010 12:012 UTC www.environmentwriter.org [Source type: Academic]

^ Benzene is soluble in water and miscible with alcohol, chloroform, ether, carbon disulfide, carbon tetrachloride, glacial acetic acid, acetone, and oils (Merck, 1989).
  • http://www.scorecard.org/chemical-profiles/html/benzene.html 10 February 2010 12:012 UTC www.scorecard.org [Source type: Academic]

^ It is miscible with organic solvents and is soluble in water.
  • Air toxics and indoor air quality in Australia - State of knowledge report: Benzene 10 February 2010 12:012 UTC www.environment.gov.au [Source type: FILTERED WITH BAYES]

.It is an excellent solvent for gums, resins, fats, &c.; sulphur, phosphorus and iodine also dissolve in it.^ Benzene is also an excellent solvent for waxes, resins, rubber and various other organic materials, but toxicological properties greatly limit use.
  • Aromatics - Chevron Phillps Chemical Company LLC - Benzene 10 February 2010 12:012 UTC www.cpchem.com [Source type: Reference]

^ Benzene is used as a constituent in motor fuels; as a solvent for fats, waxes, resins, oils, inks, paints, plastics, and rubber.
  • If You Were Harmed by Benzene Contact Our Firm about Filing a Lawsuit 10 February 2010 12:012 UTC www.weitzlux.com [Source type: News]

^ It is an excellent solvent for gums, resins, fats, &c.; sulphur , phosphorus and iodine also dissolve in it.

It sometimes separates with crystals of a solute as " benzene of crystallization," as for example with triphenylmethane, thio-p-tolyl urea, tropine, &c.
.Benzene is of exceptional importance commercially on account of the many compounds derivable from it, which are exceedingly valuable in the arts.^ Most aromatics such as benzene are produced as part of the reforming process where there is a high degree of chemical conversion to compounds of' a higher octane value.

^ Although benzene had been recognized as a component of petroleum for many years, it was not produced commercially from that source until the beginning of World War II. … .
  • Benzene - Structure, Properties, Benzene Derivatives, Uses, Health Issues 10 February 2010 12:012 UTC science.jrank.org [Source type: FILTERED WITH BAYES]

^ Benzene is a toxic chemical compound that has been used for a variety of industrial and commercial purposes since its discovery in the mid-1820s.
  • Benzene Exposure - Best Benzene Lawyer Info 10 February 2010 12:012 UTC www.mediafact.com [Source type: FILTERED WITH BAYES]

.Chemically it is one of the most interesting substances known, since it is the parent of the enormous number of compounds styled the " aromatic " or " benzenoid " compounds.^ Chemically it is one of the most interesting substances known, since it is the parent of the enormous number of compounds styled the " aromatic " or " benzenoid " compounds.

^ Benzene (Chemical Abstract Services number: 71-43-2) is a volatile liquid, with a faint characteristic, aromatic odour.
  • Environmental Registry 10 February 2010 12:012 UTC www.ebr.gov.on.ca [Source type: Reference]

^ Delocalised electrons make the molecule reactive and dangerous Benzene is one of the most interesting organic chemicals of all because it took so long for chemists to understand the structure.
  • The Chemistry of Benzene: A Hexagonal Molecule on which is Founded Aromatic Chemistry 10 February 2010 12:012 UTC organic-chemistry.suite101.com [Source type: FILTERED WITH BAYES]

.The constitution of the benzene ring, the isomerism of its derivatives, and their syntheses from aliphatic or openchain compounds, are treated in the article Chemistry.^ Benzene occurs naturally in crude oil and can also be synthesized from a variety of the compounds that are found in petroleum.
  • How to Make Benzene | eHow.com 10 February 2010 12:012 UTC www.ehow.com [Source type: General]

^ Contributor By Allan Robinson eHow Contributing Writer Article Rating: ( 0 Ratings) Benzene is an organic chemical compound with the molecular formula C6H6.
  • How to Make Benzene | eHow.com 10 February 2010 12:012 UTC www.ehow.com [Source type: General]

^ Benzene is a natural constituent of crude oil, but it is usually synthesized from other compounds present in petroleum.
  • What is benzene commonly used for? ? - Yahoo! Answers 10 February 2010 12:012 UTC answers.yahoo.com [Source type: General]

.A summary of its chemical transformations may be given here, and reference should be made to the articles on the separate compounds for further details.^ Here's why you should be: Searchable online archive access of the last 2 years of Chemical Week.
  • Lummus Lands Contract for Styrene Complex in China :: Chemical Week 10 February 2010 12:012 UTC www.chemweek.com [Source type: News]

^ It may not be as good at causing cancer as some of the other chemicals listed here, but it is found in large amounts in tobacco smoke.
  • Smoking and cancer: What’s in a cigarette? : Cancer Research UK 10 February 2010 12:012 UTC info.cancerresearchuk.org [Source type: FILTERED WITH BAYES]

^ The aforementioned separations may be further complicated by azeotropes that may form between water, ethers, and alcohols used in the alkylation process, as well as those that may form between hydrocarbons and water, alcohols, and ethers.
  • PROCESS FOR BENZENE REMOVAL FROM GASOLINE - Patent application 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

.Passed through a red-hot tube, benzene vapour yields hydrogen, diphenyl, diphenylbenzenes and acetylene; the formation of the last compound is an instance of a reversible reaction, since Berthelot found that acetylene passed through a red-hot tube gave some benzene.^ Touching: Benzene can pass through the skin.
  • Chemical Fact Sheets -- Benzene 10 February 2010 12:012 UTC dhs.wisconsin.gov [Source type: FILTERED WITH BAYES]

^ Because benzene is found in cigarettes, women who smoke pass even more benzene to their children through their breast milk.
  • Facilities Services :: Water Treatment Plant - Contaminants Explained 10 February 2010 12:012 UTC www.uaf.edu [Source type: FILTERED WITH BAYES]

^ The other competing reaction causing losses in the yield of cumene based on propylene reactant charged is the formation of oligomers of propylene such as propylene dimer and trimer which occur to a limited extent even with the large molar excesses of benzene present.
  • Process for Producing Cumene - Patent application - alkylation zone a benzene recycle stream and a propylene feed stream are contacted with an alkylation catalyst to convert 10 February 2010 12:012 UTC www.faqs.org [Source type: Reference]

.Benzene is very stable to oxidants, in fact resistance to oxidation is a strong characteristic of the benzene ring.^ Benzene is very stable to oxidants, in fact resistance to oxidation is a strong characteristic of the benzene ring.

^ It is very strong and resists heat and fire.
  • Mesothelioma, Asbestos, Benzene, and Vinyl Chloride Attorneys in Houston, Texas - Lawyers at the Law Offices of Herschel Hobson 10 February 2010 12:012 UTC www.hobsonlaw.com [Source type: FILTERED WITH BAYES]

^ Benzene is very stable.
  • Air toxics and indoor air quality in Australia - State of knowledge report: Benzene 10 February 2010 12:012 UTC www.environment.gov.au [Source type: FILTERED WITH BAYES]

.Manganese dioxide and sulphuric acid oxidize it to benzoic and o-phthalic acid; potassium chlorate and sulphuric acid breaks the ring; and ozone oxidizes it to the highly explosive white solid named ozo-benzene, C 6 H 6 O 6. Hydriodic acid reduces it to hexamethylene" (cyclo-hexane or hexa-hydro-benzene); chlorine and bromine form substitution and addition products, but the action is slow unless some carrier such as iodine, molybdenum chloride or ferric chloride for chlorine, and aluminium bromide for bromine, be present.^ Hydriodic acid reduces it to hexamethylene" (cyclo-hexane or hexa-hydro-benzene); chlorine and bromine form substitution and addition products, but the action is slow unless some carrier such as iodine, molybdenum chloride or ferric chloride for chlorine, and aluminium bromide for bromine, be present.

^ Sulphuric acid gives a benzene sulphonic acid.

^ Manganese dioxide and sulphuric acid oxidize it to benzoic and o-phthalic acid; potassium chlorate and sulphuric acid breaks the ring; and ozone oxidizes it to the highly explosive white solid named ozo-benzene, C 6 H 6 O 6.

.It is readily nitrated to nitrobenzene, two, and even three nitro groups being introduced if some dehydrator such as concentrated sulphuric acid be present.^ The nitration of benzoic acid produces m-nitrobenzene.
  • Properties of Benzene | TutorVista 10 February 2010 12:012 UTC www.tutorvista.com [Source type: Academic]

^ It is readily nitrated to nitrobenzene , two, and even three nitro groups being introduced if some dehydrator such as concentrated sulphuric acid be present.

^ The toluene fraction requires a more thorough washing with sulphuric acid in order to eliminate the thiotolene, which is sulphonated much less readily than thiophene.

.Sulphuric acid gives a benzene sulphonic acid.^ Sulphuric acid gives a benzene sulphonic acid.

^ The toluene fraction requires a more thorough washing with sulphuric acid in order to eliminate the thiotolene, which is sulphonated much less readily than thiophene.

^ When benzene is heated with concentrated sulphuric acid at 353 K for 8 hours, benzene sulphonic acid is formed.
  • Properties of Benzene | TutorVista 10 February 2010 12:012 UTC www.tutorvista.com [Source type: Academic]



Simple English

Benzene, also known as benzol, is an organic chemical compound with the formula C6H6. It is a colorless and flammable liquid with a sweet smell and a high melting point. The molecule of benzene is shaped in a six-member ring form. Benzene is carcinogenic, which means it can cause cancer. It has many real-world uses. It can be used as an additive in gasoline, plastics, synthetic rubber, dyes and it is an industrial solvent, which means it can dissolve many other chemical molecules. Benzene is also a natural part of crude oil.



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