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

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