GB765522A - Improvements in or relating to the stabilization of chlorohydrocarbons - Google Patents

Abstract

The invention comprises stabilizing a chlorohydrocarbon solvent containing up to four carbon atoms in the molecule, with a compound of the general formula <FORM:0765522/IV(b)/1> where R is a hydrocarbon radical and R1 is an unsaturated hydrocarbon radical. R may be an alkyl, alkylene, alkaryl, aralkyl or cycloalkyl radical, such as methyl, ethyl, propyl or butyl, and R1 may be an ethylene, propylene, butylene, butadiene, pentene, or decene chain. A specific example of the stabilizer is isoeugenol, i.e. 4-hydroxy-3-methoxy-1-propenylbenzene. Tetrachloroethylene and trichloroethylene are stabilized with 0.001 to 0.1 per cent by weight of the stabilizer. A second stabilizer may also be added in an amount of 0.1 to 1.0 per cent by weight. The second stabilizer preferably is an acetylenic carbinol such as methyl pentynol. In examples other secondary stabilizers used with isoeugenol are 1-nitropropane, methyl butynol and dimethyl hexynol. A list of other secondary stabilizers is given. Before adding the stabilizers tetrachloroethylene may be mixed with an organic base, such as aniline, and fractionally distilled, and may also be washed with an aqueous solution of an inorganic base, such as sodium hydroxide, dried, and distilled.ALSO:A composition comprises a chlorohydrocarbon solvent containing up to four carbon atoms in the molecule and a lightstabilizing amount of a compound of formula <FORM:0765522/III/1> where R is a hydrocarbon radical and R1 is an unsaturated hydrocarbon radical. R may be alkyl, alkylene, alkaryl, aralkyl or cycloalkyl radical, such as methyl, ethyl, propyl or butyl, and R1 may be an ethylene, propylene, butylene, butadiene, pentene or decene chain. A specific compound is isoeugenol i.e. 4-hydroxy-3-methoxy-1-propenyl-benzene. Tetrachlorethylene and trichlorethylene are stabilized with 0.001 to 0.1 per cent by weight of the stabilizer. The composition may include a second stabilizer in an amount of 0.1 to 1.0 per cent by weight. The second stabilizer preferably is an acetylenic carbinol such as methyl pentynol. In examples other secondary stabilizers used with isoeugenol are 1-nitropropane, methyl butynol and dimethyl hexynol. A list of other secondary stabilizers is given. Before adding the stabilizers tetrachloroethylene may be mixed with an organic base, such as aniline, and fractionally distilled, and may also be washed with an aqueous solution of an inorganic base, such as sodium hydroxide, dried, and distilled.