Synthesis of methyl glycolate from the hydrogenation of dimethyl oxalate on Ag/SiO2 catalyst: the effects of Ag contents and promoters

A series of silica supported silver catalysts (Ag/SiO2) with Ag loading ranging from 5% to 15% were fabricated by the ammonia-evaporation deposition-precipitation method. The effect of Ag contents on the catalytic performance of the catalysts in the selective hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG) was investigated. The result indicates that the catalyst with a 10 wt% silver loading exhibits the best catalytic activity and excellent long-term stability of more than 150h. Characteristic studies by N-2 adsorption, TPR, XRD, and XPS show that the Ag content has a significant impact on the physicochemical properties of the Ag/SiO2 catalyst. Furthermore, the influence of some additives (B, Ni, La, Ce, and Mo) on the catalytic performance of the most active 10%Ag/SiO2 catalyst in the DMO hydrogenation to MG was also studied.