ETHYLATION OF ETHYLBENZENE OVER SOME ALUMINOSILICATES WITH MOLECULAR-SIEVE STRUCTURE

A beta-zeolite, a ZSM-5 and an XRD-amorphous alumino silicate were pre pared by the usual hydrothermal technique in the presence of templatin g agents. The solids so obtained were characterised by various techniq ues and tested as catalysts for the title reaction, under typical indu strial reaction conditions (T = 180 to 260-degrees-C, P = 35 bar, ethy lbenzene WHSV = 5 h-1). For none of the three catalysts was the struct ure 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 a cid surface sites and by reaction temperature, the distribution of die thylbenzene isomers being governed by either kinetic or thermodynamic factors, rather than by shape-selective restraints.