New catalytic systems based on ceria have been used in the direct carboxylation of ethanol. The catalytic behavior of Al(2)O(3) and Nb(2)O(5) loaded ceria is compared, the latter showing a better performance. A morphological and structural study has been carried out on Nb(2)O(5)/CeO(2) 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 CO(2) or in supercritical conditions. A set-up has been developed that allows the production of quite pure DEC (>90%) with recycling of CO(2) and ethanol.
Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.