Clay-Based Solid Acid Catalyst for the Alkylation of p-Cresol with tert-Butyl Alcohol

摘要

Dealuminated montmorillonite, prepared by p-toluenesulphonic acid (pTSA) treatment, was found to be an efficient catalyst in the liquid phase alkylation of p-cresol (PC) with tertbutyl alcohol (TBA) in the synthesis of 2-tert-butyl p-cresol (2- TBC). Comparative studies revealed that catalytic activity of montmorillonite clay sample treated with 0.5 M pTSA (D3-MMT) was superior to aluminium exchanged montmorillonite (Ex- MMT) and zeolites (beta and HZSM-5) during alkylation reaction under microwave irradiation. Thermogravimetric analysis (TGDTG) showed that the deactivation of zeolites was mainly due to coke formation. Correlation studies were made for D3-MMT catalyst between volume accessibility factor (VAF) and PC conversion. These studies suggested that mesopores and types of acidities (Br?nsted, Lewis and combination of both) generated after pTSA treatment were found to play role supplementing each other in enhancing the PC conversion. The regenerated catalyst recovered from the reaction mixture under microwave heating retained its catalytic activity after three cycles under optimized conditions.