Alkylation of phenol with methyl tert-butyl ether over mesoporous material catalysts

摘要

Alkylation of phenol with methyl tert-butyl ether (MTBE) for the synthesis of tert-butyl-phenol (TBP) and 2,4-di-tert-butylphenol (2,4-DTBP) has been studied over mesoporous material catalysts with MCM-41 structure. Influence of reaction conditions as well as modification with superacid on the catalytic properties of aluminosilicate MCM-41 was evaluated. The results were compared with those of Y zeolite. It revealed that the alkylation was governed by the acidity and the pore structure of the catalyst. The distribution of products was a function of temperature. Increasing temperature promoted the selectivities toward p-TBP and 2,4-DTBP while dealkylation of 2,4-DTBP was observed at high temperature. At low temperature, the lower the space velocity was applied, the higher the phenol conversion and the 2,4-DTBP selectivity were obtained. The ratio of height to diameter of catalyst bed had almost no effect on this reaction in the range of 2-6. A mild acidity can meet the requirement for the alkylation of phenol with MTBE, while a strong acidity boasts the side-reactions such as dimerization and coke formation which results in a fast deactivation of the catalyst. Aluminosilicate MCM-41 was found to be a promising catalyst for phenol alkylation with MTBE by taking the advantage of its mild acidity and large pore diameter.