PARA-SELECTIVITY OF SAPO-5 AND MORDENITE CATALYSTS IN THE ALKYLATION OF CUMENE WITH 2-PROPANOL

Alkylation of cumene with 2-propanol was studied on SAPO-5 and mordeni te catalysts. The primary products of the alkylation on every catalyst examined here were p- and m-diisopropylbenzene (DIPB) in a ratio of 7 5:25. The p-DIPB fraction in DIPB isomers (para-selectivity) decreased with increasing yield of DIPB, due to the secondary reaction of p-DIP B to m-DIPB. On SAPO-5, mordenite and silica-alumina, this secondary r eaction proceeds through dealkylation of p-DIPB to cumene, followed by re-alkylation of the resultant cumene to m-DIPB. The dealkylation of p-DIPB would occur preferentially over that of m-DIPB. This was due to the higher reactivity of p-DIPB and probably to the reactant molecula r shape selectivity of SAPO-5 and mordenite. The pala-selectivity was improved by supporting boron oxide on SAPO-5 and mordenite; this impro vement was caused by suppression of the secondary dealkylation of p-DI PB.