Phenacyl chloride, also commonly known as chloroacetophenone, is a substituted acetophenone. It is a useful building block in

organic chemistry Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J ...

. Apart from that, it has been historically used as a

riot control agent Riot control measures are used by law enforcement, military, paramilitary or security forces to control, disperse, and arrest people who are involved in a riot, unlawful demonstration or unlawful protest. If a riot is spontaneous and irr ...

, where it is designated CN. It should not be confused with

cyanide Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...

, another agent used in chemical warfare, which has the chemical structure CN⁻.

Preparation

Phenacyl chloride is readily available and was first prepared by chlorination of acetophenone vapour. It may also be synthesized by the Friedel-Crafts acylation of

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms ...

using

chloroacetyl chloride Chloroacetyl chloride is a chlorinated acyl chloride. It is a bifunctional compound, making it a useful building block chemical. Production Industrially, it is produced by the carbonylation of methylene chloride, oxidation of vinylidene chlor ...

, with an aluminium chloride catalyst: Preparation of phenacyl chloride

Riot control agent

It was investigated, but not used, during the First and

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...

s. Because of its significantly greater toxicity, 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 Tear gas, also known as a lachrymator agent or lachrymator (), sometimes colloquially known as "mace" after the early commercial aerosol, is a chemical weapon that stimulates the nerves of the lacrimal gland in the eye to produce tears. In ...

, its use is falling as pepper spray both works and disperses more quickly than CN and is less toxic 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 A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

with tear-gas sprays in the same way that Kleenex has become strongly associated with facial tissues (a phenomenon known as a genericized trademark). Like CS gas, this compound irritates the mucous membranes (oral, nasal,

conjunctiva The conjunctiva is a thin mucous membrane that lines the inside of the eyelids and covers the sclera (the white of the eye). It is composed of non-keratinized, stratified squamous epithelium with goblet cells, stratified columnar epithel ...

l and

tracheobronchial The respiratory tract is the subdivision of the respiratory system involved with the process of respiration in mammals. The respiratory tract is lined with respiratory epithelium as respiratory mucosa. Air is breathed in through the nose t ...

). Sometimes it can give rise to more generalized reactions such as syncope, temporary loss of balance and orientation. More rarely, cutaneous irritating outbreaks have been observed and allergic contact permanent

dermatitis Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved c ...

. At high concentrations, CN may cause corneal epithelial damage and

chemosis Chemosis is the swelling (or edema) of the conjunctiva. The term derives from the Greek ''chem-'' meaning chemical and ''-osis'' meaning denoting action. A chemical reaction, or in this case, a chemical reaction of the conjunctiva which is du ...

. It has also accounted for at least five deaths, which have resulted from pulmonary injury and/or

asphyxia Asphyxia or asphyxiation is a condition of deficient supply of oxygen to the body which arises from abnormal breathing. Asphyxia causes generalized hypoxia, which affects primarily the tissues and organs. There are many circumstances that can ...

. TRPA1 (Transient Receptor Potential-Ankyrin 1) ion channel expressed on nociceptors (especially trigeminal) has been implicated as the site of action for CN, in vivo and in vitro doi=10.1016/j.taap.2008.04.005

References

External links

* {{DEFAULTSORT:Phenacyl Chloride Riot control agents Lachrymatory agents Organochlorides Aromatic ketones Acetophenones