TRICHLOROETHANE

either of two isomeric colourless, nonflammable liquids belonging to the family of organic halogen compounds. One isomer, 1,1,1-trichloroethane, is used as a replacement for carbon tetrachloride as a cold-cleaning solvent for machinery; it is not used in vapour degreasing processes because no stabilizer is available that will prevent its decomposition at high temperatures. It is produced by the reaction of 1,1-dichloroethylene and hydrogen chloride; its toxicity is very low. The other isomer, 1,1,2-trichloroethane, by contrast, is a dangerous poison that is made from acetylene, hydrogen chloride, and chlorine, or from ethylene and chlorine. Its principal use is in the manufacture of 1,1-dichloroethylene.