Kinetic modelling of the synthesis of diethyl carbonate and propylene carbonate from ethanol and 1,2-propanediol associated with CO2

Abstract

Organic carbonates have attracted considerable attention because of their numerous applications. The direct association of CO2 and alcohol to synthesise these carbonates is one of the most promising routes, when considering the economic and the environmental aspects. A significant number of researchers have worked on the catalysis and the dehydration of these reactions, but very few have dealt with the study of the thermodynamic equilibrium and the kinetics of these reactions. The objective of this work is to study the synthesis of diethyl carbonate (DEC) and propylene carbonate (PC). A parametric study was conducted by varying the temperature, the pressure and the initial concentration. Equilibrium constants were determined experimentally and compared to available published data. Kinetic models are developed based on four mechanisms, two of which are the mechanisms of Langmuir–Hinshelwood and Eley–Rideal. Mean deviations between the experimental data and the modelling were below 10% for all the mechanisms. The best fit was obtained for the mechanism of Langmuir–Hinshelwood for the synthesis of DEC and PC. Activation energies of 100 kJ/mol and 77 kJ/mol were determined for the synthesis of DEC and PC, respectively.