Kinetic study for styrene carbonate synthesis via CO2 cycloaddition to styrene oxide using silica-supported pyrrolidinopyridinium iodide catalyst

Abstract

Reaction kinetics for heterogeneous catalysis of styrene carbonate (SC) synthesis via CO2 cycloaddition to styrene oxide (SO) using silica-supported pyrrolidinopyridinium iodide (SiO2-PPI) catalyst has been investigated. The results obtained from the mixing study and theoretical analysis based on Thiele modulus (< 0.4) and effectiveness factor (∼1.0) revealed no external and internal mass transfer limitations. The experimental results were compared with pseudo-homogeneous (PH) and Langmuir-Hinshelwood (LH), Eley-Rideal (ER) heterogeneous kinetic model. The experimental data was found to be the best fit with the ER model among the three kinetic models. Moreover, the Arrhenius and Eyring equations were used to determining the activation energy (i.e. 64.9 kJ mol–1) and thermodynamic activation parameters such as enthalpy of activation (ΔH‡= 60.6 kJ mol–1), the entropy of activation (ΔS‡ = –148.3 J mol–1 K–1) and Gibb’s free energy (ΔG‡ = 115.9 kJ mol–1 at 373 K). The SiO2-PPI heterogeneous catalyst exhibited excellent reusability: up to five cycles without any substantial decrease in activity and selectivity towards SC formation.