Ultra-selective p-xylene production through cycloaddition and dehydration of 2,5-dimethylfuran and ethylene over tin phosphate

A series of SnPO catalysts was systematically prepared and characterized in detail to provide an insight into the structure-activity relationship for PX production from 2,5-dimethylfuran (DMF) and ethylene. SnPO possessing tetrahedrally coordinated Sn(IV) as the active sites exhibited an ultra-high PX yield of 93%. The outstanding catalytic performance of SnPO could be ascribed to two aspects: a controllable adjustment in acid sites (tetrahedrally coordinated Sn(IV) or P-OH) by altering the molar ratio of P/Sn, which leads to enhancement in the main reaction and inhibition for the side reactions; the improved mass transfer efficiency and high tolerance to deactivation caused by carbon deposition because of the mesoporous structure. The DFT calculation revealed that tetrahedrally coordinated Sn(IV) was more efficient than P-OH groups for PX production. The ultra-high activity and stability of SnPO should allow significant progress in the efficient production of bio-based PX in the near future.