Efficacy of mesoporous solid catalyst AlMCM-41 in vapour phase reaction of isobutylbenzene with isopropanol

Mesoporous molecular sieves AlMCM-41 of Si/Al ratios (27, 52, 78, and 104) were synthesized hydrothermally and characterized by physicochemical techniques viz., XRD, BET, ICP-AES analysis and 27Al-MAS-NMR. The catalytic activity was examined in the vapour phase isopropylation of isobutylbenzene with isopropanol at 200, 225, 250, and 275 °C over the catalysts. The products were found to be 4-isopropylcumene (4-IBC), 3-isopropylcumene (3-IBC), 2-isopropylcumene (2-IBC) and diisopropyl isobutylbenzene (DIIBB). Conversion of isobutylbenzene decreases with increase in temperature. The selectivity to 4-IBC is maximum at 200 °C and decreases with increase in temperature. Isomerisation of 4-IBC to 3-IBC is observed at high temperature. The catalyst AlMCM-41 (Si/Al = 27) showed superior catalytic performance in this reaction. Various parameters viz., temperature, feed ratio, WHSV and time on stream were investigated and results are discussed.