Cyanogen chloride

Structural formula
General
Surname	Cyanogen chloride
other names	Cyanochloride Cyanogen chloride
Molecular formula	ClCN
Brief description	colorless gas irritating to tears
External identifiers / databases
CAS number 506-77-4 EC number 208-052-8 ECHA InfoCard 100.007.321 PubChem 10477 Wikidata Q415075
properties
Molar mass	61.47 g · mol -1
Physical state	gaseous
density	1.218 g cm −3 (4 ° C)
Melting point	−6.9 ° C
boiling point	12.9 ° C
Vapor pressure	134 k Pa (20 ° C) 190 kPa (30 ° C) 360 kPa (50 ° C)
solubility	soluble in ethanol and diethyl ether
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 280-330-314 EUH: 071 P: ?
MAK	Switzerland: 0.3 ml m −3 or 0.8 mg m −3
Toxicological data	10 mg min m −3 ( TC Lo ,  human ,  inh. )
Thermodynamic properties
ΔH f 0	138.0 kJ / mol
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Cyanogen chloride , also called cyan chloride , is a chemical substance that is also used as a chemical warfare agent. Systematically, cyanogen chloride is the nitrile of the inconsistent chloroformic acid .

Extraction and presentation

Cyanogen chloride can be obtained by reacting potassium tetracyanozincate (II) or sodium cyanide with chlorine .

${\displaystyle \mathrm {K_{2}[Zn(CN)_{4}]+4\ Cl_{2}\longrightarrow 4\ ClCN+2\ KCl+ZnCl_{2}} }$

${\displaystyle \mathrm {NaCN+Cl_{2}\longrightarrow NaCl+ClCN} }$

properties

Cyanogen chloride forms a colorless gas. The compound melts at −6.9 ° C and boils at 12.9 ° C under normal pressure . The triple point is −6.9 ° C and 0.449 bar. According to Antoine, the vapor pressure function results from log ₁₀ (P) = A− (B / (T + C)) (P in bar, T in K) with A = 4.66177, B = 1074.1 and C = −54.458 in the temperature range from 196 to 286 K. The mean heat of vaporization in this temperature range is up to 32.2 kJ · mol ⁻¹ . The critical point is at a temperature of 175 ° C, a pressure of 59.92 bar and a density of 0.273 g · cm ^−3. The compound is very soluble in ethanol , gasoline , ether and chlorinated solvents. The molecule is quickly hydrolyzed on contact with water or caustic soda .

${\displaystyle \mathrm {Cl{-}C{\equiv }N+H_{2}O\rightarrow HO{-}C{\equiv }N+HCl} }$

The reaction with ammonia gives cyanamide .

${\displaystyle \mathrm {Cl{-}C{\equiv }N+NH_{3}\rightarrow H_{2}N{-}C{\equiv }N+HCl} }$

In the presence of traces of hydrochloric acid or ammonium chloride , violent and strongly exothermic trimerization to 2,4,6-trichloro-1,3,5-triazine can take place. A tetramer as 2,4-dichloro-6-isocyanodichloro- s- triazine is also formed as a by-product .

use

During the First World War , cyanogen chloride was mixed with hydrogen cyanide to increase its deadly effect. In contrast to hydrocyanic acid, cyanogen chloride works more slowly because the cyanide ion is released more slowly. Cyanogen chloride was first used in 1916 by the Entente . The most important technical use is the controlled conversion to 2,4,6-trichloro-1,3,5-triazine, a starting material for the production of active ingredients with herbicidal effect.

Cyanogen chloride or cyanogen bromide are used in organic chemistry as reagents for cyanation and the synthesis of heterocycles. For example, a cyano group can be introduced directly into aromatics under Friedel-Crafts conditions . Of alkenes and alkynes direct addition takes place with acid catalysis. Both compounds can be used to remove a C-terminal protective group from genetically engineered insulin fusion protein, thereby obtaining correctly folded insulin . The reaction with sulfur trioxide gives the highly reactive chlorosulfonyl isocyanate .

${\displaystyle \mathrm {SO_{3}+ClCN\longrightarrow ClSO_{2}NCO} }$

Protective measures

Cyanogen chloride can be neutralized with bases such as alkali hydroxides, ammonia , amines and pyridine . Gas mask filters are impregnated with cyclic amines in order to counteract the "mask-breaking" effect of cyanogen chloride.

See also

• List of chemical warfare agents
• Blood warfare agent

Individual evidence

1. ↑ ^{a b} Entry on cyanogen chloride. In: Römpp Online . Georg Thieme Verlag, accessed on July 15, 2014.
2. ↑ ^{a b c d e f g h i j k} Entry on cyanogen chloride in the GESTIS substance database of the IFA , accessed on January 28, 2018(JavaScript required) .
3. ↑ Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 506-77-4 or cyanogen chloride ), accessed on November 2, 2015.
4. ↑ Entry on cyanogen chloride in the ChemIDplus database of the United States National Library of Medicine (NLM) .
5. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-19.
6. ↑ Georg Brauer , with the collaboration of Marianne Baudler a . a. (Ed.): Handbook of Preparative Inorganic Chemistry . 3rd, revised edition. tape I . Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , pp. 630 .
7. ^ ^{A b} Stull, DR: Vapor Pressure of Pure Substances. Organic and Inorganic Compounds in Ind. Eng. Chem. 39 (1947) 517-540, doi : 10.1021 / ie50448a022
8. ↑ Latscha, HP; Kazmaier, U .; Klein, HA: Organic Chemistry - Chemistry Basics II , 6th edition Springer-Verlag 2008, ISBN 978-3-540-77106-7 , p. 309.
9. ↑ PG Urben; MJ Pitt: Bretherick's Handbook of Reactive Chemical Hazards . 8th edition, Vol. 1, Butterworth / Heinemann 2017, ISBN 978-0-08-100971-0 , p. 87.
10. ↑ ^{a b c d} E. Gail, S. Gos, R. Kulzer, J. Lorösch, A. Rubo, M. Sauer, R. Kellens, J. Reddy, N. Steier, W. Hasenpusch: Inorganic Cyano Compounds , in : Ullmann's Encyclopedia of Technical Chemistry , Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 2012; doi : 10.1002 / 14356007.a08_159.pub3 .
11. ^ E-EROS Encyclopedia of Reagents for Organic Synthesis , 1999–2013, John Wiley and Sons, Inc., entry for Cyanogen Bromide, accessed January 20, 2015 .
12. ↑ EH Bartlett, C. Eaborn, DRM Walton: Interaction of aryltrimethylstannanes with cyanogen chloride and bromide. A route to aryl cyanides in J. Organomet. Chem. 46 (1972) 267-269, doi : 10.1016 / S0022-328X (00) 88327-8 .
13. ↑ R.Ch. Paul, RL Chauhan, R. Parkash: in J. Sci. Ind. Res. 33 (1974) 31-38.
14. ↑ JV Bodrikov, BV Danova: in Zh. Org. Khim 8 (1972) 2462-2467.
15. ↑ J. Iwai, T. Iwashige, Y. Yuma, N. Nakamune, K. Shinozaki: Studies on Acetylenic Compounds. XXXIX. The Addition Reaction of Cyanogen Bromide to Acetylenic Compounds in Chem. Pharm. Bull. 12 (1964) 1446-1451, doi : 10.1248 / cpb.12.1446 , pdf .
16. ↑ Beate Meichsner and Uwe Wirth: Insulin - Protein with a long history - The key to diabetes therapy. In: Chemistry in Our Time. 2009, 43, 5, pp. 340–346, doi: 10.1002 / ciuz.200900486 .
17. ↑ Roderich Count: chlorosulfonyl isocyanate in: Organic Syntheses . 46, 1966, p. 23, doi : 10.15227 / orgsyn.046.0023 ; Coll. Vol. 5, 1973, p. 226 ( PDF ).
18. ↑ Patent EP0294613A1 - Process and plant for the continuous production of chlorosulfonyl isocyanate ( Hoechst AG 1988).

Web links

• Ansyco: Infrared spectrum of cyanogen chloride
• WHO: Cyanogen Chloride in Drinking-water (PDF; 100 kB)