Catalyst Deactivation for Enhancement of Selectivity in Alcohols Amination to Primary Amines

Selective synthesis of valuable primary amines is an important target in modern industry. Amination of alcohols with ammonia is an economically efficient and environmentally friendly process for primary amine synthesis. This consecutive reaction yields a mixture of primary, secondary, and tertiary amines. High selectivity to primary amines is an important challenge of alcohol amination. Carbon deposition on the catalyst surface is conventionally considered an undesirable process, which leads to poor catalytic performance. In this paper, carbon deposition produced by catalyst pretreatment with alcohols under the optimized conditions has been employed for major enhancement of the selectivity of alcohol amination to primary amines (from 30 to 50 to 80-90%). This extremely positive effect of carbon deposition on the amination selectivity arises from steric hindrance in hydrogenation of bulky secondary imines as intermediate products over partially carbon-decorated cobalt nanoparticles.