GB617572A - A method of stabilizing halogeno-organic compounds - Google Patents

Abstract

Dehydrohalogenation of halogeno organic compounds is retarded by the addition thereto of an inhibitor comprising a condensation product of an aldehyde with a primary amine. The inhibitors are effective in glass or metal vessels and are particularly effective for compounds containing halogen in a side chain attached to an aromatic nucleus, e.g. chloroalkyl-benzenes and chloroalkyl-chlorobenzenes other compounds specified being chlorinated wax and kerosene, wet carbon tetrachloride and trichloroethylene. About 0.1 per cent by weight of halogenated compound is usually an effective quantity of inhibitor. A mixture of inhibitors may be used. Inhibitors mentioned are N-salicylal-N1-hydroxyethyl-ethylene diamine, salicylol - ethanolamine, - phenyl-ethanolamine, -p-phenylenediamine, -2,5-diaminotoluene dihydrochloride, -2-nitroso-4-chloroaniline, -b -naphthylamine, 2,4-dihydroxybenzal-4-amino-1,3-dimethylbenzene, p-isopropylbenzal-p-anisidine and butyral-3,4-diaminotoluene being prepared by the condensation of the appropriate aldehyde and amine and practical details are given for the preparation of the first six. In examples the decomposition of mixed isomers of chloroethyldichlorobenzenes in the presence of Monel metal (Monel is a Registered Trade Mark) is inhibited by: (1) salicylal-hydroxyethylethylene diamine; (2) salicylal-ethanolamine; (3) primary salicylal-phenylethanolamine, and (4) salicylal-p-phenylenediamine, in the presence of lead by (6) salicylal-2,5-diaminotoluene and in the presence of stainless steel by (5) and (6) salicylal-2,5-diaminotolueme; (7) salicylal-3,4-diaminotoluene; (8) salicylal - 2 - amino - 5 - hydroxytoluene; (9) salicylal-b -naphthylamine; (10) the condensation product of a chlorinated aminated kerosene and salicylaldehyde; (11) 2,4 - dihydroxy - 4 - amino - 1,3 - dimethylbenzene; (12) m-nitrobenzal-hydroxyethylethylene diamine; (13) p-isopropylbenzal-p-anisidine; (14) butyral-3,4-diaminotoluene, and (15) benzal-3,4-diaminotoluene, decomposition of pentachloroethane in the presence of Monel metal is inhibited in (16) by salicylalhydroxyethylethylene diamine and that of mixed isomers of bromo-ethyl-dichlorobenzenes in (17) by salicylal-p-anisidine and in (18) by salicylal-p-phenylene diamine.