Trichloromethyl group

Some simple trichloromethyl compounds include trichloromethane, also known as chloroform (), 1,1,1-trichloroethane (), and hexachloroethane (). Trichloromethanol is however unstable, reflecting the lability associated with the RO-C-Cl center. Indeed, triphosgene (bis(trichloromethyl) carbonate, OC(OCCl3)2) fragments upon heating by scission of a C-Cl bond. It is used as a substitute for phosgene. Because the trichloromethyl group is relatively electronegative, the behavior of trichloromethyl-substituted compounds can differ sharply vs the behavior of the methyl parents. The acidity constant (pKa) of trichloroacetic acid is 0.77, whereas that of acetic acid is 4.76. In other words, trichloroacetic acid is 1000x the stronger acid. In a related manner, the trichloromethyl aldehyde (chloral) tends to hydrate to give chloral hydrate . ==Trichloromethyl arenes==

Many trichloromethylarenes can be prepared by chlorination of the corresponding methyl arenes. For example toluene and the xylene isomers as well as their substituted derivatives can often be converted to the corresponding trichloromethyl derivatives simply by treatment with chlorine. The conversion involves a free radical reaction: : : These trichloromethyl compounds are produced on an industrial scale as precursors to other useful compounds. Partial hydrolysis of benzotrichloride provides a route to benzoyl chloride: : : ==Bioactive derivatives==

A trichloromethyl-containing agricultural chemical is nitrapyrin, which inhibits nitrification, i.e. it enhances the efficiency of fertilizers. Trichloromethyl-containing insecticides include metrifonate and Folpet. The list of trichloromethyl-containing pharmaceuticals includes the anorectic drug Amfecloral and the sedative triclofos. ==Trichloromethyl radical==

The trichloromethyl radical () is a well known but transient intermediate in reactions. It is the agent responsible for the toxicity of carbon tetrachloride. ==References==