Alkylation of phenol with methanol was carried out over Lewis acid ion exchanged y-zeolites, FeY, ZnY, CdY and LaY at temperatures of 523,573,623,673 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 Velocity (WHSV) were examined for high phenol conversion and product selectivity. Phenol conversion decreased with increase of temperature over all the catalysts due to coke deposition. Selectivity to o-cresol decreased with increase of temperature as it, once formed, became the reactant for formation of 2,6-xylenol. Selectivity to 2,6-xylenol increased with increase of temperature indicating high activation energy for its formation. Selectivity to anisole, although formed less than 10% over all the catalysts, decreased with 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 showed preferential blocking of strong acid sites by coke deposits and hence these site dependent formations of o-cresol and 2,6-xylenol were greatly reduced but free weak acid site dependent anisole formation increased with time.
|Original language||English (US)|
|Number of pages||8|
|Journal||Proceedings of the Indian Academy of Sciences: Chemical Sciences|
|State||Published - Dec 1 1998|