Silicotungstate-modified zirconia as an efficient catalyst for phenol tert-butylation

The alkylation of phenol with tert-butanol was investigated using zirconia modified with silicotungstic acid (STA) as catalysts. Under the reaction conditions of 140 °C, tert-butanol/phenol molar ratio of 2 and LHSV of 4 h−1, the most active catalyst 15 % STA on ZrO2 calcined at 750 °C, gave 95.4 % phenol conversion with selectivity to 2-tert-butyl phenol 4.3 %, 4-tert-butyl phenol 59.2 % and 2,4-di-tert-butyl phenol 35.8 %.