chloroform(redirected from Chcl3)
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(also trichloromethane), CHCl3, a colorless liquid, with a pungent odor and sweet burning taste. Chloroform has a boiling point of 61.15°C and a density of 1.488 g/cm3 (at 20°C). It is practically insoluble in water but is soluble in most organic solvents. In the light, it is slowly decomposed by atmospheric oxygen with the formation of phosgene, chlorine, hydrogen chloride, and formic acid; consequently, 1 percent ethyl alcohol is added as a stabilizer.
Many reactions of chloroform proceed through the intermediate formation of dichlorocarbene, :CCl2, for example, the synthesis of isocyanides by the reaction of chloroform with primary amines in the presence of alkalies and the reaction of chloroform with the alcoholates RONa, which leads to the formation of ortho esters.
Chloroform is produced by chlorination, for example, of methane, acetone, or alcohol. Considerable chloroform is used in industry in the production of the freon difluorochloromethane, CF2ClH; it is also used as a solvent.
Chloroform is an anesthetic. It exists in two types of preparations. The first is primarily for external use, in medical practice for massages and in histology as a tissue preservative and fixative; occasionally it is used internally in the form of drops to relieve certain symptoms, for example, nausea. The second type of chloroform preparation is used as an anesthetic; it is specially purified and has a strong anesthetizing effect and relatively high toxicity.