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Acetophenone
Acetophenone-2D-skeletal.png
Acetophenone-from-xtal-3D-balls.png
IUPAC name
Other names Phenyl methyl ketone, ACP
Identifiers
CAS number 98-86-2 Yes check.svgY
PubChem 7410
SMILES
InChI
InChI key KWOLFJPFCHCOCG-UHFFFAOYAT
ChemSpider ID 7132
Properties
Molecular formula C8H8O
Molar mass 120.15 g mol−1
Density 1.028 g/cm³
Melting point

19-20 °C

Boiling point

202 °C

Solubility in water 5.5 g/L at 25°C
12.2 g/L at 80°C
Hazards
MSDS External MSDS
EU classification Harmful Xn
NFPA 704
NFPA 704.svg
2
 
0
 
Flash point 77 °C
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

Acetophenone is the organic compound with the formula C6H5C(O)CH3. It is the simplest aromatic ketone. This colourless, viscous liquid is a precursor to useful resins and fragrances.[1]

Contents

Production

Acetophenone can be obtained by a variety of methods. In industry, acetophenone is recovered as a by-product of the oxidation of ethylbenzene, which mainly gives ethylbenzene hydroperoxide for use in the production of propylene oxide.[1]

Uses

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Precursor to resins

Commercially significant resins are produced from treatment of acetophenone with formaldehyde and base. The resulting polymers are conventionally described with the formula [(C6H5C(O)CH]x(CH2) x}n, resulting from aldol condensation. These materials are components of coatings and inks. Modified acetophenone-formaldehyde resins are produced by the hydrogenation of the aforementioned ketone-containing resins. The resulting polyol can be further crosslinked with diisocyanates.[1] These modified resins are again found in coatings, inks, as well as adhesives.

Precursor to styrene

In instructional laboratories, acetophenone is converted to styrene in a two step process that illustrates the reduction of carbonyls and the dehydration of alcohols:

4 C6H5C(O)CH3 + NaBH4 + 4 H2O → 4 C6H5CH(OH)CH3 + NaOH + B(OH)3

A similar process is used industrially but the hydrogenation step to 1-phenylethanol is done over a copper catalyst.[1]

C6H5CH(OH)CH3 → C6H5CH=CH2 + H2O

Use in pharmaceutical and related areas

Acetophenone is a raw material for the synthesis of some pharmaceuticals[2] [3] and is also listed as an approved excipient by the U.S. FDA.[4] In a 1994 report released by five top cigarette companies in the U.S., acetophenone was listed as one of the 599 additives to cigarettes.[5]

Niche uses

Acetophenone is used to create fragrances that resemble almond, cherry, honeysuckle, jasmine, and strawberry. It is used in chewing gum. Being prochiral, acetophenone is also a popular test substrate for asymmetric transfer hydrogenation experiments.

Natural occurrence

Acetophenone occurs naturally in many foods including apple, cheese, apricot, banana, beef, and cauliflower.

Pharmacology

In the late 1800s and early 1900s, acetophenone was used in medicine.[6] It was marketed as a hypnotic and anticonvulsant under brand name Hypnone. The typical dosage was 0.12 to 0.3 milliliters.[7] It was considered to have superior sedative effects to both paraldehyde and chloral hydrate.[8] In humans, acetophenone is metabolized to benzoic acid, carbonic acid, and acetone.[9]

References

  1. ^ a b c d Hardo Siegel, Manfred Eggersdorfer “Ketones” in Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH, 2002, Wienheim. doi:10.1002/14356007.a15_077
  2. ^ Sittig, Marshall (1988). Pharmaceutical Manufacturing Encyclopedia. pp. 39,177. ISBN 0815511442, 9780815511441.  
  3. ^ Gadamasetti, Kumar; Tamim Braish (2007). Process Chemistry in the Pharmaceutical Industry, Volume 2. pp. 142–145. ISBN 0849390516, 9780849390517.  
  4. ^ http://www.accessdata.fda.gov/scripts/cder/iig/index.cfm
  5. ^ "What's in a cigarette?". http://quitsmoking.about.com/cs/nicotineinhaler/a/cigingredients.htm. Retrieved 2006-05-31.  
  6. ^ The Merck Index, 12th Edition
  7. ^ Bartholow, Roberts. "A Practical Treatise On Materia Medica And Therapeutics." Appleton & Co, 1908.
  8. ^ Norman, Conolly. "Cases illustrating the sedative effects of aceto-phenone." Journal of Mental Science, Vol 32, p 519. 1887.
  9. ^ "Hypnone - The new hypnotic." J Am Med Assoc. Vol 23, p. 632. 1885.

1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

ACETOPHENONE, or PHENYL-METHYL KETONE, C8H8O or C6H5CO.CH3, in chemistry, the simplest representative of the class of mixed aliphatic-aromatic ketones. It can be prepared by distilling a mixture of dry calcium benzoate and acetate, Ca(O2CC6H5)2 + (CH3CO2)2Ca = 2CaCO3 + 2 C6H5CO.CH3, or by condensing benzene with acetyl chloride in the presence of anhydrous aluminium chloride (C. Friedel and J. M. Crafts), C6H6+CH3COCl == HCl + C6H5COCH3. It crystallizes in colourless plates melting at 20°C. and boiling at 202°C.; it is insoluble in water, but readily dissolves in the ordinary organic solvents. It is reduced by nascent hydrogen to the secondary alcohol C6H5.CH.OH.CH3 phenyl-methyl-carbinol, and on oxidation forms benzoic acid. On the addition of phenylhydrazine it gives a phenylhydrazone, and with hydroxylamine furnishes an oxime C6H5.CH3.C=N.OH melting at S9°C. This oxime undergoes a peculiar rearrangement when it is dissolved in ether and phosphorus pentachloride is added to the ethereal solution, the excess of ether distilled off and water added to the residue being converted into the isomeric substance acetanilide, C6H5NHCOCH3, a behaviour shown by many ketoximes and known as the Beckmann change (see Berichte, 1886, 19, p. 988). With sodium ethylate in ethyl acetate solution it forms the sodium derivative of benzoyl acetone, from which benzoyl acetone, C6H5.CO.CH2.CO.CH3, can be obtained by acidification with acetic acid. When heated with the halogens, acetophenone is substituted in the aliphatic portion of the nucleus; thus bromine gives phenacyl bromide, C6H6CO.CH2Br. Numerous derivatives of acetophenone have been prepared, one of the most important being orthoaminoacetophenone, NH2.C6H4.CO.CH3, which is obtained by boiling orthoaminophenylpropiolic acid with water. It is a thick yellowish oil boiling between 242° C. and 250° C. It condenses with acetone in the presence of caustic soda to a quinoline. Acetonyl-acetophenone, C6H5.CO.CH2.CH2.CO.CH3, is produced by condensing phenacyl bromide with sodium acetoacetate with subsequent elimination of carbon dioxide, and on dehydration gives aa-phenyl-methyl-furfurane. Oxazoles are produced on condensing phenacyl bromide with acid-amides (M. Lewy, Berichte, 1887, 20, p. 2578). K. L. Paal has also obtained pyrrol derivatives by condensing acetophenone-acetoacetic-ester with substances of the type NH2R.

5 I10 600 150 I 00 I 00 400 400 600 2500 absorb


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