Synthesis, Characterization, and Use of NbV/CeIV-Mixed Oxides in the Direct Carboxylation of Ethanol by using Pervaporation Membranes for Water Removal

New catalytic systems based on ceria have been used in the direct carboxylation of ethanol. The catalytic behavior of Al2O3 and Nb2O5 loaded ceria is compared, the latter showing a better performance. A morphological and structural study has been carried out on Nb2O5/CeO2 catalysts in order to explain their behavior in catalysis. Pervaporation membranes have been used for water separation. The synthesis of diethylcarbonate (DEC) has been carried out either in a liquid phase (ethanol) pressurized with CO2 or in supercritical conditions. A set-up has been developed that allows the production of quite pure DEC (>90?%) with recycling of CO2 and ethanol.