CO2 Cycloaddition to Styrene Oxide Catalysed by ZnBr2 Impregnated Rice Husk Ash Silica: Structural and Kinetics Studies

摘要

A series of ZnBr2 impregnated on rice husk ash silica catalysts were synthesised via the wet impregnation method for the CO2 cycloaddition to styrene oxide reaction. The X-ray diffraction (XRD) analysis indicates that the impregnation resulted in the deterioration of the silica's pore channels. Catalyst with 0.5 w/w of Zn (0.5 wt ZnBr2-SiO2) was highly active in the CO2 cycloaddition to styrene oxide. The conversion of styrene oxide (StO) was 89.1 , with the styrene carbonate (SC) selectivity of 92.1 under the optimum conditions (130 degrees C, 60 bar, 3 h and solventless). Additionally, the universality of 0.5 wt ZnBr2-SiO2 was also studied with other epoxides, and it shows good to excellent activity. The catalytic performance of the 0.5 wt ZnBr2-SiO2 remains constant after being reused three consecutive times. The activation energy of the reaction was determined to be 89.06 kJ/mol.