Chloroacetyl chloride
Encyclopedia
Chloroacetyl chloride is a chlorinated acyl chloride
Acyl chloride
In organic chemistry, an acyl chloride is an organic compound with the functional group -CO-Cl. Their formula is usually written RCOCl, where R is a side chain. They are usually considered to be reactive derivatives of carboxylic acids. A specific example of an acyl chloride is acetyl chloride,...

. It is a bifunctional compound
Bifunctional
In organic molecules, functional groups are atom or atoms which are responsible for the characteristic properties of that molecule with the exceptions of double and triple bonds which are also functional groups....

, making it a useful building block chemical.

Production

Industrially, it is produced by the carbonylation
Carbonylation
Carbonylation refers to reactions that introduce carbon monoxide into organic and inorganic substrates. Carbon monoxide is abundantly available and conveniently reactive, so it is widely used as a reactant in industrial chemistry.-Organic chemistry:...

 of methylene chloride, oxidation of vinylidene chloride, or the addition of chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

 to ketene
Ketene
A ketene is an organic compound of the form R'RC=C=O. The term is also used specifically to mean ethenone, the simplest ketene, where R' and R are hydrogen atoms.Ketenes were first studied as a class by Hermann Staudinger.-Formation:...

. It may be prepared from chloroacetic acid
Chloroacetic acid
Chloroacetic acid, industrially known as monochloroacetic acid is the organochlorine compound with the formula ClCH2CO2H. This carboxylic acid is a useful building-block in organic synthesis.-Production:...

 and thionyl chloride
Thionyl chloride
Thionyl chloride is an inorganic compound with the formula SOCl2. It is a reactive chemical reagent used in chlorination reactions. It is a colorless, distillable liquid at room temperature and pressure that decomposes above 140 °C. Thionyl chloride is sometimes confused with sulfuryl...

, phosphorus pentachloride, or phosgene
Phosgene
Phosgene is the chemical compound with the formula COCl2. This colorless gas gained infamy as a chemical weapon during World War I. It is also a valued industrial reagent and building block in synthesis of pharmaceuticals and other organic compounds. In low concentrations, its odor resembles...

.

Reactions

Chloroacetyl chloride is bifunctional—the acyl chloride easily forms ester
Ester
Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...

s and amide
Amide
In chemistry, an amide is an organic compound that contains the functional group consisting of a carbonyl group linked to a nitrogen atom . The term refers both to a class of compounds and a functional group within those compounds. The term amide also refers to deprotonated form of ammonia or an...

s, while the other end of the molecule is able to form other linkages, e.g. with amines. The use of chloroacetyl chloride in the synthesis of lidocaine
Lidocaine
Lidocaine , Xylocaine, or lignocaine is a common local anesthetic and antiarrhythmic drug. Lidocaine is used topically to relieve itching, burning and pain from skin inflammations, injected as a dental anesthetic or as a local anesthetic for minor surgery.- History :Lidocaine, the first amino...

 is illustrative:

Applications

The major use of chloroacetyl chloride is as an intermediate in the production of alachlor
Alachlor
Alachlor is an herbicide from the chloroacetanilide family. Its mode of action is elongase inhibition, and inhibition of geranylgeranyl pyrophosphate cyclisation enzymes, part of the gibberellin pathway.-Uses:...

 and butachlor
Butachlor
Butachlor is an herbicide of the acetanilide class. It is used as a selective pre-emergent herbicide....

; an estimated 100 million pounds are used annually. Some chloroacetyl chloride is also used to produce phenacyl chloride, another chemical intermediate, also used as a tear gas. Phenacyl chloride is synthesized in a Friedel-Crafts acylation of benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

, with an aluminium chloride
Aluminium chloride
Aluminium chloride is the main compound of aluminium and chlorine. It is white, but samples are often contaminated with iron trichloride, giving it a yellow colour. The solid has a low melting and boiling point. It is mainly produced and consumed in the production of aluminium metal, but large...

 catalyst:

Safety

Like other acyl chlorides, reaction with other protic compounds such as amines, alcohols, and water generates hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....

, making it a lachrymator.
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