GB422563A - Improvements in the manufacture and production of aliphatic amines - Google Patents

Abstract

Aliphatic amines containing up to four carbon atoms in the alkyl groups are prepared from compounds of the formula ROX, where R is an alkyl group containing up to four carbon atoms and X is hydrogen or an alkyl group containing up to four carbon atoms, by heating the compounds with more than an equimolecular amount of ammonia or a primary or secondary aliphatic amine containing up to four carbon atoms in the alkyl group or groups; the reaction is effected under a pressure of more than about 50 atm. and in the presence of a dehydrating catalyst, and preferably at 300--450 DEG C. The process may be conducted cyclically, with return of the excess of ammonia or amine to the reaction. When ammonia is used, a primary amine is normally the principal product. When it is desired to obtain mainly a secondary amine from ammonia, the corresponding primary amine is added to the reaction mixture; to restrain the formation of tertiary amine, the latter may also be added. In the examples: (1) methyl alcohol and an excess of ammonia are passed at 380 DEG C. and 80 atm. over alumina gel in a tube lined with manganese-copper; methylamines, mainly monomethylamine, are obtained; (2) ethyl alcohol and an excess of ammonia, together with ethylamine and triethylamine, are passed at 400 DEG C. and 200 atm. over alumina gel; diethylamine is recovered from the product by fractional distillation; the excess of ammonia and the mono- and tri-ethylamine, which are present in the product in amounts corresponding to those taken, are returned to the reaction; (3) n-propyl alcohol and an excess of ammonia, together with n-propylamine, are treated as in example 2; di-n-propylamine is recovered, as well as n-propylamine in the amount taken; (4) dimethyl ether and an excess of ammonia are passed at 375 DEG C. and 150 atm. over alumina gel; methylamines, mainly monomethylamine, are obtained; (5) isobutyl alcohol and an excess of isobutylamine are passed at 380 DEG C. and 200 atm. over alumina gel; di- and triisobutylamines, mainly the former, are obtained; (6) ethyl alcohol and an excess of diethylamine are passed at 375 DEG C. and 180 atm. over alumina gel; triethylamine is obtained. Specification 421,596 is referred to.