Composition-Dependent Copper-Based Binary Metal Alloys for Hydrogenation of Dimethyl Succinate to 1,4-Butanediol

This study investigates the hydrogenation of dimethyl succinate (DMS) to 1,4-butanediol (BDO) over a series of Cu-based catalysts supported on SiO2. A preliminary investigation of monometallic catalysts indicated that Cu/SiO2 was the only catalyst capable of producing BDO. Consequently, bimetallic Cu-based catalysts containing various metals were synthesized, and the results suggest that CuFe/SiO2 exhibited the best performance for BDO production. The effect of the Cu-to-Fe ratio was examined, revealing that adding Fe led to the formation of CuFe2O4, which decreased the overall particle size and increased the surface metal sites. It was found that the Cu4Fe0.5/SiO2 catalyst produced BDO with a yield of 58.4% at 200 °C, 0.10 h–1, and 4 MPa H2, demonstrating its superior catalytic performance. Contact time analysis was performed to elucidate the reaction mechanism and calculate the reaction rates. It was revealed that the reaction proceeds from dimethyl succinate → γ-butyrolactone → BDO → tetrahydrofuran, propanol, and butanol, in which the reaction between GBL and BDO is a reversible one. This reversible reaction is the key reaction inhibiting the production of BDO. This reaction was effectively suppressed over the Cu4Fe0.5/SiO2 catalyst, resulting in a high formation of BDO from DMS due to the synergistic interaction between Cu and Fe.