Bimetallic Pt–Sn/γ-alumina catalyst for highly selective liquid phase hydrogenation of diethyl succinate to γ-butyrolactone

Platinum–tin bimetallic catalyst on γ-alumina support was prepared by impregnation method and was reduced by sodium borohydride at room temperature. XRD and XPS characterization revealed that platinum was reduced to Pt0 while, tin was probably partially reduced to Sn2+ due to the low temperature reduction method and Sn0 was completely absent, avoiding the formation of Pt–Sn alloy. Pt–Sn/γ-alumina (Pt 1%, Sn 9%) thus prepared was found to give almost complete selectivity to γ-butyrolactone in liquid phase hydrogenation of diethyl succinate. A plausible reaction pathway is proposed involving Pt–O–Sn state and high selectivity to GBL is due to the Lewis acidity of Sn2+/4+.