Organic carbonates synthesis improved by pervaporation for CO2 utilisation

Abstract

This work is focused on the synthesis of organic carbonates from CO2 and ethanol. A parametric study of the synthesis of diethyl carbonate from ethanol is performed in a 100 mL batch reactor. The influence of pressure and temperature is studied and we prove that the presence of water strongly decreases the yield in diethyl carbonate as an equilibrium is quickly reached. One method to improve this yield is to remove water from the reaction mixture to shift the equilibrium toward the formation of carbonates. The chemical methods give good results but separation and regeneration associated steps are prohibitive. For these reasons, a physical technique like pervaporation is chosen to remove water. The study of a pervaporation cell with membrane PERVAP 4100 gives good results for the dehydration of ethanol alone even at low concentrations of water from 0.33 %wt to 0.15 %wt. Twelve experiments on the dehydration of a mixture of ethanol, diethyl carbonate and water are performed. The calculated separation factors show a very good selectivity for water. That means that even in the presence of diethyl carbonate, the membrane has still a selective water permeability.

Keywords

• co2
• utilisation
• pervaporation
• organic carbonates
• dehydration