Improved di:isopropylbenzene(s) prodn. - by disproportionation of cumene in presence of zeolite catalyst modified by pptn. of silica from alkyl orthosilicate vapour

摘要

Prodn. of diisopropylbenzenes (I), by conversion of a cumene-contg. feedstock in the presence of a beta-zeolite contg. 0.001-0.5 g pptd. SiO2 per g zeolite (II). Specifically quartz deposit is produced by treating the zeolite with vaporised orthosilicate of formula Si(OR)4 (III) (with R = 1-5C alkyl) until sufficient (III) is adsorbed followed by calcination for 2-48 hrs. at 400-600 deg.C in air; (II) has mol. ratio SiO2/Al2O3 = (10-150):1, and is a cationic zeolite in its H-form; reaction is carried out at 90-250 (pref. 100-180) deg.C and 1.01-101.33 bar in a continuous solid-bed reactor system, under a N-contg. atmos. with mol. ratio N/hydrocarbon = 0.05-10, and with throughput = 0.2-50 g/hr./g catalyst. USE/ADVANTAGE - The method provides a process for the prodn. of (I) by disproportionation of cumene; the above modification increases the stability of the zeolite catalyst used, without adversely affecting its good disproportionation selectivity (SD)