World Library  
Flag as Inappropriate
Email this Article

Cyanamide

Article Id: WHEBN0002926930
Reproduction Date:

Title: Cyanamide  
Author: World Heritage Encyclopedia
Language: English
Subject: Compounds of carbon, Nitrile, Cyanogen, Ammonia, Graphitic carbon nitride
Collection: Cyanamides, Inorganic Carbon Compounds, Nitrogen Metabolism
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Cyanamide

Cyanamide
Full skeletal formulas of cyanamide, both tautomers
Space-filling model of the cyanamide molecule, nitrile tautomer
Space-filling model of the cyanamide molecule, diimide tautomer
Names
IUPAC names
Cyanamide,
aminomethanenitrile
Other names
Amidocyanogen, carbamonitrile, carbimide, carbodiimide, cyanoamine, cyanoazane, N-cyanoamine, cyanogenamide, cyanogen amide, cyanogen nitride, diiminomethane, hydrogen cyanamide, methane diimide
Identifiers
 Y
ChEBI  Y
ChEMBL  Y
ChemSpider  Y
DrugBank  Y
EC number 206-992-3
Jmol-3D images Image
KEGG  Y
PubChem
RTECS number GS5950000
UNII  Y
UN number 2811
Properties
CH2N2
Molar mass 42.040 g/mol
Appearance Crystalline solid
Density 1.28 g/cm3
Melting point 44 °C (111 °F; 317 K)
Boiling point 260 °C (500 °F; 533 K) (decomposes)
83 °C at 6.7 Pa
140 °C at 2.5 kPa
85 g/100 ml (25 °C)
Solubility in organic solvents soluble
Hazards
Safety data sheet ICSC 0424
Toxic (T)
R-phrases R20, R25, R27, R36/38, R43
S-phrases (S1/2), S3, S22, S36/37, S45
NFPA 704
1
4
3
Flash point 141 °C (286 °F; 414 K)
US health exposure limits (NIOSH):
PEL (Permissible)
none[1]
REL (Recommended)
TWA 2 mg/m3
N.D.[1]
Related compounds
Related compounds
Calcium cyanamide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
 Y  (: Y/N?)

Cyanamide is an nitrile group attached to an amino group. Although it is similar in structure to hydrogen cyanide, it is not as toxic. Derivatives of this compound are also referred to as cyanamides, the most common being calcium cyanamide (CaCN2).

Contents

  • Tautomers and self-condensations 1
  • Production, reactions, uses 2
  • Environmental aspects 3
  • Safety 4
  • References 5
  • External links 6

Tautomers and self-condensations

Containing both a nucleophilic and electrophilic site within the same molecule, cyanamide undergoes various reactions with itself. Cyanamide exists as two tautomers, one with the connectivity NCNH2 and the other with the formula HNCNH ("diimide" tautomer). The NCNH2 form dominates, but in a few reactions (e.g. silylation) the diimide form appears to be important.

Cyanamide dimerizes to give 2-cyanoguanidine (dicyandiamide). This decomposition process is disfavored by acids and is inhibited by low temperatures. The cyclic trimer is called melamine.

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 compounds containing an acidic proton. Water, hydrogen sulfide, and hydrogen selenide react with cyanamide to give urea, thiourea, and selenourea, respectively:

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

In this way, cyanamide behaves as 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.[2]

Cyanamide is a common agricultural rest-breaking agent applied in spring to stimulate uniform opening of buds, early foliation and bloom. Cyanamide can effectively compensate for the moderate lack of chilling units accumulated in the previous autumn and save the harvest that would otherwise be lost. It is particularly effective for woody plants such as berries, grapes, apples, peaches and kiwifruit. Overdosage, high concentration and error in timing of application can damage the buds (especially of peach trees).[3]

Environmental aspects

Cyanamide degrades via hydrolysis to urea, an excellent fertilizer. Fungi, like Myrothecium verrucaria, accelerate this process utilizing the enzyme cyanamide hydratase.[4]

Safety

Cyanamide has a modest toxicity in humans.[5] 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.[5]

References

  1. ^ a b "NIOSH Pocket Guide to Chemical Hazards #0160".  
  2. ^ Thomas Güthner; Bernd Mertschenk (2006). "Cyanamides". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim:  
  3. ^ Powell, A. (1999). Action Program for Dormex Application on Peaches. Auburn University. Retrieved 2010-05-24.
  4. ^ Stransky H and Amberger A (1973). "Isolation and properties of a cyanamide hydratase (EC 4.2.1) from Myrothecium verrucaria". Z. Pflanzenphysiol. 70: 74–87.
  5. ^ 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".  

External links

  • International Chemical Safety Card 0424
  • "NIOSH Pocket Guide to Chemical Hazards #0160".  
  • OSHA guideline for cyanamide
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.