Hydrogenolysis of dimethyl maleate on Cu/ZnO/Al2O3 catalysts

The gas-phase hydrogenolysis of dimethyl maleate at 10 bar and 513 K was investigated over a series of co-precipitated Cu/ZnO/Al2O3 catalysts. High copper surface areas were obtained with a molar Al content of 5 % in the catalysts. Upon variation of composition at fixed alumina content, copper surface areas increased until the molar ratio exceeded Cu/Zn = 2.1. At the given reaction conditions, dimethyl maleate was completely converted to dimethyl succinate, which further reacted to methanol, gamma -butyrolactone, tetrahydrofuran, and water over all catalysts. Initial deactivation of catalysts was mainly caused by a loss of copper surface area. The catalyst with a molar Cu/Zn ratio of 1:2 was found to be most active and stable under-reaction conditions.