Synthesis of Co-Based Catalysts Using a Rotating Packed Bed for Selective Hydrogenation of Acetonitrile

Abstract

Highly efficient Co-based catalysts are significant for the selective hydrogenation of nitriles to amines. In this work, highly efficient mixed metal oxide (Co/MMO) catalysts confined with Co particles were prepared in a rotating packed bed (RPB), following the preparation processes of layered double hydroxides (LDH) coprecipitation and LDH-MMO transformation. The influences of the Co content, premixing mode, crystallizing mode, and time on the structure of the catalyst, as well as its catalytic performance for acetonitrile hydrogenation were investigated. It was found that CoAl-LDH can be formed in the Co content range of 43-71 wt % in RPB. In addition, enhancing micromixing performance in premixing and crystallizing processes is beneficial for the synthesis of particles with small size, uniform particle size, and high ratio of length (L) to thickness (T). Finally, the highly efficient Co/MMO catalyst with an acetonitrile conversion of 99.17% and ethylamine selectivity of 96.12% was prepared under optimal operating conditions. Compared with Raney-Co catalysts, the Co/MMO catalyst with a lower Co content has higher conversion and selectivity by 6.67 and 4.82%, respectively. These results provide a new strategy for preparing catalysts with high efficiency and low cost for selective hydrogenation of nitrile.