3 research outputs found
Cobaltâcatalyzed amination of 1,3âcyclohexanediol and 2,4âpentanediol in supercritical ammonia
The oneâstep procedure of amination of bifunctional secondary alcohols to diamines has been investigated in a continuous fixedâbed reactor. Application of supercritical NH3 as a solvent and reactant suppressed catalyst deactivation and improved selectivities to amino alcohol intermediates, whereas selectivities to diamines remained poor (8-10%). The main reason for the low diamine selectivity of 1,3âdihydroxy compounds is water elimination leading to undesired monofunctional products via α,ÎČâunsaturated alcohol, ketone or amine intermediates. This side reaction does not occur with 1,4âdihydroxy compounds which afford high aminol and diamine selectivities under similar conditions. Amination of secondary diols with ammonia was found to be faster, but less selective than that of the corresponding primary 1,3âpropanedio