Thermodynamics and Kinetics Study of Diethyl Carbonate (DEC) Synthesis from CO2, Ethanol, and Epoxides with Various Catalysts

Abstract

Carbon dioxide (CO2) has been the main contributor for global warming over the past decades. However, it can potentially be utilized as raw material of valuable products, such as organic carbonate compound namely diethyl carbonate (DEC). Formation of DEC via indirect route from CO2 and ethanol is accompanied with epoxides as dehydrating agent. This work has been devoted to study thermodynamics and kinetics of indirect DEC synthesis using ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO) with various catalysts. Data from scientific journals and previous experiments conducted at Laboratory of Thermodynamics, ITS were analyzed in this study. Based on the value of (ΔG), it was found that indirect synthesis using EO is the most spontaneous reaction, followed by BO and PO, respectively. Simulation using Aspen HYSYS V8.8 also reveals that reactant and product system after 3 hours of reactions falls into vapor-liquid region and superheated region. Meanwhile, kinetics evaluation of experiment using PO and KI/EtONa catalyst showed that the aforementioned reactions are exothermic due to decreasing value of reaction constant upon reaching certain temperature. Based on Arrhenius equation while presuming that the reaction is elementary and non-elementary, activation energy was estimated as 55.62 kJ/mol and 54.80 kJ/mol, respectively. Furthermore, the use of KI/EtONa as catalyst resulted the highest yield among other catalysts namely KI, KI/CeO2, and KI/Zeolite.