Isopropylation of benzene with 2-propanol over substituted large pore aluminophosphate-based molecular sieves

Abstract

Large pore aluminophosphate-based molecular sieves like AlPO4-5, MAPO-5, MAPO-5 and ZAPO-5 were synthesised hydrothermally using triethylamine as a structure directing agent. These materials were characterised by X-ray diffraction (XRD), 27Al and 31P MAS-NMR, ICP-MS, n-butylamine-TPD, BET and SEM. The catalytic performance of these materials was tested for isopropylation of benzene with 2-propanol at 250, 300, 350 and 400°C. The products were cumene, P-DIPB (P-diisopropyl-benzene) and m-DIPB (m-diisopropylbenzene). MnAPO-5 was found to be more active than the other catalysts. Maximum conversion (20%) was noted at 350°C over MnAPO-5. The selectivity to DIPB was found to decrease with time on stream but the selectivity to cumene showed an increase after 3 h of time on stream.