The influence of phosphotungstic acid acidity on Al-MCM-41 in t-butylation of phenol with t-butyl alcohol

Al-MCM-41 (Si/Al = 20) molecular sieve was synthesized hydrothermally and phosphotungstic acid (PW) of 10, 20 and 40 wt% was supported on it. Their catalytic performance was examined in the vapour phase alkylation of phenol with tert-butyl alcohol (TBA) in the temperature range 190–275 °C. The major products were 2-tert-butyl phenol (2-TBP), 4-tert-butyl phenol (4-TBP), 2,4-di-tert-butyl phenol (2,4-DTBP) and small amounts of undesired products. 4-TBP was obtained as the major product with high selectivity. The results revealed that 20 wt% PW supported on Al-MCM-41 is found to be more active than other catalysts. The effects of molar feed ratio, space velocity and reaction temperature on conversion and products selectivity were studied and the results are discussed. The reaction parameters were optimized to obtain high selectivity of 4-TBP at high phenol conversion.