Alkylation of phenol with methanol over ion-exchanged Y-zeolites

Alkylation of phenol with methanol was carried out over Lewis acid ion exch anged Y-zeolites, FeY, ZnY, CdY and LaY at temperatures of 523, 573, 623, 6 73 and 698 K. The products obtained were o-cresol, 2, 6-xylenol and anisole . The effects of phenol to methanol mole ratio and Weight Hourly Space Velo city (WHSV) were examined for high phenol conversion and product selectivit y. Phenol conversion decreased with increase of temperature over all the ca talysts due to coke deposition. Selectivity to o-cresol decreased with incr ease of temperature as it, once formed, became the reactant for formation o f 2,6-xylenol. Selectivity to 2,6-xylenol increased with increase of temper ature indicating high activation energy for its formation. Selectivity to a nisole, although formed less than 10% over all the catalysts, decreased wit h increase of temperature due to its conversion to o-cresol and then to 2,6 -xylenol. In addition, selectivity to anisole also decreased with decrease of phenol to methanol feed ratio and WHSV. The study of time on stream show ed preferential blocking of strong acid sites by coke deposits and hence th ese site dependent formations of o-cresol and 2, 6-xylenol were greatly red uced but free weak acid site dependent anisole formation increased with tim e.