Phenacyl chloride

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Phenacyl chloride
Skeletal formula
Ball-and-stick model
IUPAC name
Other names
alpha-Chloroacetophenone, 2-Chloroacetophenone, Chloromethyl phenyl ketone, Phenyl chloromethyl ketone
532-27-4 YesY
ChemSpider 10303 N
Jmol-3D images Image
PubChem 10757
Molar mass 154.59 g·mol−1
Appearance white to gray crystalline solid[1]
Odor pungent and irritating[1]
Density 1.324 g/cm3
Melting point 54 to 56 °C (129 to 133 °F; 327 to 329 K)
Boiling point 244.5 °C (472.1 °F; 517.6 K)
Vapor pressure 0.005 mmHg (20 °C)[1]
Main hazards Combustible[1]
EU classification Toxic T
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 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas 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
Flash point 88 °C (190 °F; 361 K)
Lethal dose or concentration (LD, LC):
417 mg/m3 (rat, 15 min)
600 mg/m3 (mouse, 15 min)
465 mg/m3 (rabbit, 20 min)
490 mg/m3 (guinea pig, 30 min)
159 mg/m3 (human, 20 min)
850 mg/m3 (human, 10 min)[2]
US health exposure limits (NIOSH):
TWA 0.3 mg/m3 (0.05 ppm)[1]
TWA 0.3 mg/m3 (0.05 ppm)[1]
15 mg/m3[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
 N verify (what isYesY/N?)
Infobox references

Phenacyl chloride is a substituted acetophenone. It is a useful building block in organic chemistry. Apart from that, it has been historically used as a riot control agent, where it is designated CN.[3]


Phenacyl chloride is readily available commercially. It may be synthesized by the Friedel-Crafts acylation of benzene using chloroacetyl chloride, with an aluminium chloride catalyst:[4]

Preparation of phenacyl chloride.png

Riot control agent[edit]

It was investigated, but not used, during the First and Second World Wars.

Because of its significantly greater toxicity,[5] it has largely been supplanted by CS gas. Even though CN is still supplied to paramilitary and police forces in a small pressurized aerosol known as “Mace” or tear gas, its use is falling as pepper spray both works and disperses more quickly than CN.

The term "Mace" came into being because it was the brand-name invented by one of the first American manufacturers of CN aerosol sprays. Subsequently, In the United States, Mace became synonymous with tear-gas sprays in the same way that Kleenex has become strongly associated with tissue papers (a phenomenon known as a genericized trademark).[citation needed]

Like CS gas, this compound irritates the mucous membranes (oral, nasal, conjunctival and tracheobronchial). Sometimes it can give rise to more generalized reactions such as syncope, temporary loss of balance and orientation.[5] More rarely, cutaneous irritating outbreaks have been observed and allergic contact permanent dermatitis.[3]

At high concentrations CN has caused corneal epithelial damage and chemosis. It has also accounted for at least five deaths, which have resulted from pulmonary injury and/or asphyxia.[6]


  1. ^ a b c d e f g "NIOSH Pocket Guide to Chemical Hazards #0119". National Institute for Occupational Safety and Health (NIOSH). 
  2. ^ "alpha-Chloroacetophenone". Immediately Dangerous to Life and Health. National Institute for Occupational Safety and Health (NIOSH). 
  3. ^ a b Treudler, R.; Tebbe, B.; Blume-Peytavi, U.; Krasagakis, K.; Orfanos, C. E. (1999). "Occupational contact dermatitis due to 2-chloracetophenone tear gas". British Journal of Dermatology 140 (3): 531–534. doi:10.1046/j.1365-2133.1999.02724.x. PMID 10233281. 
  4. ^ Levin, N.; Hartung, W. H. (1955). "ω-Chloroisonitrosoacetophenone". Org. Synth. ; Coll. Vol. 3, p. 191 
  5. ^ a b Ballantyne, B.; Swanston, D. W. (1978). "The comparative acute mammalian toxicity of 1-chloroacetophenone (CN) and 2-chlorobenzylidene malononitrile (CS)". Archives of Toxicology 40 (2): 75–95. doi:10.1007/BF01891962. PMID 350195. 
  6. ^ Blain, P. G. (2003). "Tear Gases and Irritant Incapacitants: 1-Chloroacetophenone, 2-Chlorobenzylidene Malononitrile and Dibenz[b,f]-1,4-Oxazepine". Toxicological Reviews 22 (2): 103–110. doi:10.2165/00139709-200322020-00005. PMID 15071820.