GB384714A - Improvements in or relating to the catalytic production of amines from alcohols and a - Google Patents

Abstract

Amines are prepared by passing an aliphatic alcohol and ammonia at a raised temperature, e.g. 250-500 DEG C. over a contact mass comprising a porous rigid gel impregnated with an oxide acting as a dehydrating catalyst. The gel may be silica gel, alumina gel, or chromium oxide gel, and the oxide with which the gel is impregnated may be alumina, thoria or oxide of boron, tungsten or titanium. The contact mass may be prepared by adding to the gel, after or in the course of its preparation, the dehydrating oxide or a compound convertible into such oxide. In the examples, (1) silica gel is evacuated at 400 DEG C., cooled in vacuo, immersed in aluminium nitrate solution, dried, and ignited at 400 DEG C.; a mixture of butanol vapour and ammonia is passed at 325 DEG C. over the contact mass so prepared, yielding butylamines and a little butylene; the yields are compared with those obtained when an unsupported aluminium phosphate catalyst is used; (2) methanol vapour and ammonia are passed at 340 DEG C. over the contact mass described in example 1, yielding methylamines and a little dimethyl ether; (3) a contact mass comprising boron trioxide supported on silica gel is prepared, as in example 1, from silica gel and ammonium borate; methanol vapour and ammonia are passed over the contact mass at 350 DEG C., yielding methylamines. Specification 355,867 is referred to.ALSO:A contact mass for the manufacture of amines from aliphatic alcohols and ammonia comprises a porous rigid gel impregnated with an oxide acting as a dehydrating catalyst. The gel may be silica gel, alumina gel, or chromium oxide gel, and the oxide with which the gel is impregnated may be alumina, thoria, or oxide of boron, tungsten or titanium. The contact mass may be prepared by adding to the gel, after or in the course of its preparation, the dehydrating oxide or a compound covertible into such oxide. In the examples (1) silica gel is evacuated at 400 DEG C., cooled in vacuo, immersed in aluminium nitrate solution, dried, and ignited at 400 DEG C.; (2) a contact mass comprising boron trioxide supported on silica gel is prepared, as in example (1), from silica gel and ammonium borate. Specification 355,867 is referred to.