Effect of Different Nano-Sized Silica Sols as Supports on the Structure and Properties of Cu/SiO 2 for Hydrogenation of Dimethyl Oxalate

摘要

Cu/ x -SiO 2 catalysts with 4, 10, and 20 nm silica sols as supports was produced by ammonia evaporation method and characterized. Different nano-sized silica sols as supports significantly affected the structure and catalytic properties of the copper catalysts for ethylene glycol synthesis from dimethyl oxalate. Compared with Cu/20-SiO 2 and Cu/4-SiO 2 catalysts, the catalytic performance and stability of Cu/10-SiO 2 catalyst were greatly enhanced. The Cu/10-SiO 2 catalyst showed 99.9% conversion with 94% EG selectivity and a lifetime of over 3080 h if it is calculated by industrial weight liquid hourly space velocity (WLHSV) of 0.5 h ?1 . The Cu/10-SiO 2 catalyst has one of the longest lifetimes among the catalysts and is a good alternative catalyst for this reaction. Improvement in the catalytic performance and stability of Cu/10-SiO 2 is attributed to the proper S BET , D p and larger dispersion of copper. In addition, the supports of Cu/10-SiO 2 catalyst have smaller particles than that of Cu/20-SiO 2 ; thus, the migration and growth of copper species in catalysts are restrained during the reaction.