Effect of support on palladium catalyst for aqueous-phase hydrogenation of maleic acid to succinic acid

The synthesis of succinic acid (SA), one of the monomers used to create poly(butylene succinate), a type of biodegradable plastic, has become a crucial and even bottleneck technology for the industry's development. Herein, a series of Pd-based catalysts were prepared with amorphous TiO2, CeO2 and ZrO2 as the supports and applied in the aqueous-phase hydrogenation of maleic acid (MA) to SA at a low temperature about 60 & DEG;C. The metal-support interaction and the structure-activity relationship of Pd-based catalysts were investigated. It was found that the Pd/CeO2 catalyst was substantially more active than the Pd/TiO2 and Pd/ZrO2 catalysts. The strong interaction between the CeO2 and Pd inhibited the agglomeration of Pd during the reduction and reaction process, leading to much higher Pd dispersion. The exposure of more active sites for the adsorption of MA molecules accelerated the MA hydrogenation process, giving a much higher activity in the hydrogenation of MA to SA.