Oxidative carbonylation of propylene glycol to propylene carbonate by copper-based catalysts

Abstract

BackgroundDevelopment of copper-based catalyst and associated reaction engineering for heterogeneous oxidative carbonylation of propylene glycol (PG) to optimize conversion and selectivity. Coupling reactions with reverse water-gas shift reaction is a good way of realizing CO2 utilization. MethodThe synthesis of propylene carbonate (PC) through the oxidative carbonylation of propylene glycol is carried out in a pressurized autoclave reactor using solid copper catalysts. Various types of copper and composite copper/ceria catalysts are prepared by coprecipitation or impregnation method. Significant findingsReaction temperature and the roles of sodium acetate (SA) and potassium iodide (KI) additives are systematically studied with pure copper to map out the optimum reaction condition, i.e., a 100 °C-reaction using 2.0 g of PG mixed with 8.0 g of solvent with 0.02 g of SA and 0.02 g of KI additives. Using this optimized condition, the copper and composite copper/ceria catalysts are investigated with the composite catalysts composed of metallic copper on ceria, showing the highest selectivity of 94.7% towards PC. These findings in this study should pave way for the development of practical industrial scale CO2 utilization processes.