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CS gas

CS gas
Skeletal formula of CS gas
Space-filling model of CS gas
Names
Preferred IUPAC name
[(2-Chlorophenyl)methylidene]propanedinitrile
Other names
2-(2-Chlorobenzylidene)malononitrile
2-Chlorobenzalmalononitrile
o-Chlorobenzylidene malononitrile
OCBM
Tear gas
Identifiers
2698-41-1 YesY
3D model (Jmol) Interactive image
ChemSpider 16644 YesY
ECHA InfoCard 100.018.435
4158
Properties
C10H5Cl N2
Molar mass 188.6 g/mol
Appearance White crystalline powder
Colourless gas when burned
Odor pepper-like
Density 1.04 g/cm3
Melting point 93 °C (199 °F; 366 K)
Boiling point 310 °C (590 °F; 583 K)
insoluble
Vapor pressure (mm Hg) 3.4 × 10−5 at 20 °C
Hazards
Safety data sheet See: data page
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Lethal dose or concentration (LD, LC):
1806 mg/m3 (rat, 45 min)
2753 mg/m3 (mouse, 20 min)
1802 mg/m3 (rabbit, 10 min)
2326 mg/m3 (guinea pig, 10 min)
US health exposure limits (NIOSH):
PEL (Permissible)
 TWA 0.05 ppm (0.4 mg/m3)
REL (Recommended)
 C 0.05 ppm (0.4 mg/m3) [skin]
IDLH (Immediate danger)
 2 mg/m3
Related compounds
Related compounds
 SDBS

5-chloro-2-quinolinecarbonitrile
6-chloro-2-quinolinecarbonitrile
7-chloro-2-quinolinecarbonitrile
Supplementary data page
Refractive index (n),
Dielectric constant (εr), etc.
Thermodynamic
data
 Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY  (what is YesYN ?)
Infobox references

5-chloro-2-quinolinecarbonitrile
6-chloro-2-quinolinecarbonitrile
7-chloro-2-quinolinecarbonitrile

The compound 2-chlorobenzalmalononitrile (also called o-chlorobenzylidene malononitrile) (chemical formula: C10H5ClN2), a cyanocarbon, is the defining component of a tear gas commonly referred to as CS gas, which is used as a riot control agent. Exposure causes a burning sensation and tearing of the eyes to the extent that the subject cannot keep their eyes open, and a burning irritation of the nose, mouth and throat mucous membranes causing profuse coughing, mucous nasal discharge, disorientation, and difficulty breathing, partially incapacitating the subject. CS gas is an aerosol of a volatile solvent (a substance that dissolves other active substances and that easily evaporates) and 2-chlorobenzalmalononitrile, which is a solid compound at room temperature. CS gas is generally accepted as being non-lethal. It was first synthesized by two Americans, Ben Corson and Roger Stoughton, at Middlebury College in 1928, and the chemical's name is derived from the first letters of the scientists' surnames.

CS was developed and tested secretly at Porton Down in Wiltshire, England, in the 1950s and 1960s. CS was used first on animals, then subsequently on British Army servicemen volunteers. CS has less effect on animals due to "under-developed tear-ducts and protection by fur".

CS is synthesized by the reaction of 2-chlorobenzaldehyde and malononitrile via the Knoevenagel condensation:

The reaction is catalysed with weak base like piperidine or pyridine. The production method has not changed since the substance was discovered by Corson and Stoughton. Other bases, solvent free methods and microwave promotion have been suggested to improve the production of the substance.


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Wikipedia

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