Supercritical fluids as reaction media in the ethylbenzene disproportionation on ZSM-5

Ethylbenzene disproportionation over HZSM-5, was studied in a wide range of temperatures and pressures including supercritical conditions, aiming to determine the effect of variations in reaction media properties on reaction parameters, focusing on the potential advantages of supercritical conditions, previously discussed in literature. The effect of pressure on conversion has been explained in terms of changes in the reaction media produced by pressure variations, whereas at high pressure conditions temperature has effect not only on the kinetics but also on media density. Pressure dos not have effect on the selectivity to the main product, diethylbenzene; however temperature should be taken into account since above certain temperatures secondary reactions are favoured. Conversion close to the equilibrium one has been reached at 400 degrees C and 45 bar, demonstrating that supercritical fluids are a satisfactory reaction media for ethylbenzene disproportionation. (C) 2010 Elsevier B.V. All rights reserved.