Deactivation of Cu/SiO2 catalyst for dimethyl oxlate hydrogenation to ethylene glycol

摘要

The catalytic hydrogenation of dimethyl oxalate (DMO) to ethylene glycol (EG) is the second step of indirect synthesis of glycol from syngas, which employs Cu/SiO2 catalyst. These Cu containing catalysts are quite active for the reaction. However, deactivation was observed in the pilot plant that will likely prevent use of such catalysts in commercial production .In this paper, the deactivation of Cu/SiO2 catalyst is investigated. The Cu/SiO2 catalyst is deactivated under the reaction conditions: temperature of 483 K, pressure of 2MP, DMO LHSV of characterized by XRD, BET surface area measurements and TG-DTG. It is found that the crystallite size of Cu in the deactivated catalyst is much bigger than those in the fresh catalyst by XRD. From TG-DTG data ,the deactivated catalyst weight decreases significantly after 300 ,?? which indicated that polymer may exist in the deactivated catalyst. Experimental studies indicate that EG effectively accelerates deactivation of the copper catalyst due to polymerization of EG in the pore of catalyst. Therefore, it is concluded that the deactivation of the Cu/SiO2 catalyst is mainly caused by the growth in the Cu crystallite sizes and carbonaceous deposits.