ETHYLATION OF ETHYLBENZENE OVER SOME ALUMINOSILICATES WITH MOLECULAR-SIEVE STRUCTURE

A beta-zeolite, a ZSM-5 and an XRD-amorphous alumino silicate were prepared by the usual hydrothermal technique in the presence of templating agents. The solids so obtained were characterised by various techniques and tested as catalysts for the title reaction, under typical industrial reaction conditions (T = 180 to 260-degrees-C, P = 35 bar, ethylbenzene WHSV = 5 h-1). For none of the three catalysts was the structure and the pore size of the solid shown to play a significant role in directing the selectivity towards a particular diethylbenzene isomer. A major role appeared to be played by the concentration of Bronsted acid surface sites and by reaction temperature, the distribution of diethylbenzene isomers being governed by either kinetic or thermodynamic factors, rather than by shape-selective restraints.