Effect of supercritical conditions on the transalkylation of diethylbenzene with benzene

The use of supercritical fluids in hydrocarbons transformation reactions shows important advantages: increase of reaction rate and selectivity as well as increase of the catalyst lifetime in the supercritical region with respect to the subcritical one. The objective of this work was to study the effect of supercritical conditions on the transalkylation of diethylbenzene with benzene to produce ethylbenzene. Both CO2 and free-solvent systems, using different acidic commercial zeolites (Beta, Y and Mordenite) as catalyst, have been explored. For all the catalysts, supercritical conditions improved the catalyst performance only in the free-solvent system, results which have been explained in terms of the different densities and diethylbenzene diffusion coefficients of the reaction mixture. © 2005 Elsevier B.V. All rights reserved