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Cyanamide
Cyanamide.svg
Cyanamide-3D-balls.png
IUPAC name
Other names Amidocyanogen, carbamonitrile, carbimide, carbodiimide, cyanoamine, cyanoazane, N-cyanoamine, cyanogenamide, cyanogen nitride, hydrogen cyanamide
Identifiers
CAS number 420-04-2 Yes check.svgY
PubChem 9864
EC number 206-992-3
UN number 2811
RTECS number GS5950000
SMILES
Properties
Molecular formula CH2N2
Molar mass 42.040 g/mol
Appearance Crystalline solid
Density 1.28 g/cm3
Melting point

44 °C

Boiling point

260 °C (decomp.)
83 °C at 6.7 Pa
140 °C at 2.5 kPa

Solubility in water 85 g/100 ml (25 °C)
Solubility in organic solvents soluble
Hazards
MSDS ICSC 0424
EU Index 615-013-00-2
EU classification Toxic (T)
R-phrases R21, R25, R36/38, R43
S-phrases (S1/2), S3, S22, S36/37, S45
NFPA 704
NFPA 704.svg
1
4
3
 
Flash point 141 °C
Related compounds
Related compounds Calcium cyanamide
 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

Cyanamide is an organic compound with the formula CN2H2. This white solid is widely used in synthetic organic chemistry as well as in agriculture. It is also used as an alcohol deterent drug in Canada, Europe and Japan, but not in the United States. The molecule features a nitrile group attached to an amino group. Although it is similar in structure to hydrogen cyanide, it is not as toxic. Derivative of this compound are also referred to as cyanamides, the most common being calcium cyanamide (CaCN2).

Contents

Production, reactions, uses

Cyanamide is produced by hydrolysis of calcium cyanamide, which in turn is prepared from calcium carbide via the Frank-Caro process.

CaCN2 + H2O + CO2 → CaCO3 + H2NCN

The conversion is conducted on slurries, consequently most commercial cyanamide is sold as an aqueous solution.

The main reaction exhibited by cyanamide involves additions of protic reagents. Water, hydrogen sulfide, and hydrogen selenide add to give urea, thiourea, and selenourea, respectively:

H2NCN + H2E → H2NC(E)NH2 (E = O, S, Se)

Thus, cyanamide is a dehydration agent and thus can induce condensation reactions. Alcohols, thiols, and amines react analogously to give alkylisoureas, "pseudothioureas," and guanidines. The anti-ulcer drug cimetidine is generated using such reactivity. Related reactions exploit the bifunctionality of cyanamide to give heterocycles, and this latter reactivity is the basis of several pharmaceutical syntheses such as the aminopyrimidine imatinib) and agrichemicals Amitrol (3-Amino-1,2,4-triazole) and Hexazinone. The hair-loss treatment Minoxidil and the anthelmintic (worm-killing) drugs Albendazole, Flubendazole, and Mebendazole feature 2-aminoimidazole substructures derived from cyanamide.[1]

Environmental aspects

Cyanamide degrades via hydrolysis to urea, an excellent fertilizer. Microorganisms, e.g. the bacterium Myrothecium verrucaria, accelerate this process utilizing the enzyme cyanamide hydratase.

Safety

Cyanamide has a modest toxicity in humans.[2] Workplace exposure to hydrogen cyanamide sprays or exposure in people living in the vicinity of spraying have been reported as causing respiratory irritation, contact dermatitis, headache, and gastrointestinal symptoms of nausea, vomiting, or diarrhea.[2]

References

  1. ^ Thomas Güuthner,Bernd Mertschenk, "Cyanamides" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2006.
  2. ^ a b Schep L, Temple W, Beasley M (January 2009). "The adverse effects of hydrogen cyanamide on human health: an evaluation of inquiries to the New Zealand National Poisons Centre". Clinical Toxicology (Philadelphia, Pa.) 472 (1): 58–60. doi:10.1080/15563650802459254. PMID 18951270.  

External links


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

CYANAMIDE, NC NH 2j the amide of normal cyanic acid, obtained by the action of ammonia on cyanogen chloride, bromide or iodide, or by the desulphurization of thio-urea with, mercuric oxide; it is generally prepared by the latter process. It forms white crystals, which melt at 40° C., and are readily soluble in water, alcohol and ether. Heated above its melting point it polymerizes to di-cyandiamide (CN2H2)2, which at 150° C. is transformed into the polymer n-tri-cyantriamide or melamine (CN 2 H 2) 3, the mass solidifying. Nascent hydrogen reduces cyanamide to ammonia and methylamine. It gives mono-metallic salts of the type NC NHM when treated with aqueous or alcoholic solutions of alkalis. Di-metallic salts are obtained by heating cyanates alone, e.g. calcium, or cyanides in a current of nitrogen, e.g. barium.

Calcium cyanamide has assumed importance in agriculture since the discovery of its economic production in the electric furnace, wherein calcium carbide takes up nitrogen from the atmosphere to form the cyanamide with the simultaneous liberation of carbon. It may also be produced by heating lime or chalk with charcoal to 2000° in a current of air. The cornmercial product (which is known in Germany as "Kalkstickstof") contains from 14 to 22% of nitrogen, which is liberated as ammonia when the substance is treated with water; to this decomposition it owes its agricultural value. It appears that with soils which are not rich in humus or not deficient in lime, calcium cyanamide is almost as good, nitrogen for nitrogen, as ammonium sulphate or sodium nitrate; but it is of doubtful value with peaty soils or soils containing little lime, nor is it usefully available as a top-dressing or for storing.


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