Higher conversion rate of phenol alkylation with diethylcarbonate by using synthetic fly ash-based zeolites

In this study, zeolites prepared from fly ash pretreated with hydrochloric acid were used for catalysis. The synthesis was performed by a pre-fusion hydrothermal activation with low crystallization temperature (60 degrees C) and using both seawater and distilled water. The synthetic zeolites were tested via the base-catalyzed gas-phase alkylation of phenol using diethyl carbonate as an innovative alkylating agent, thus obtaining phenol conversions up to 95% with a selectivity of more than 85% in phenetole. These data indicate that the newly-formed zeolites are very selective for the O-ethylation of phenol also at high temperatures. Moreover, the results show that the zeolites formed from fly ash have a greater catalytic activity than that shown by commercial NaY and synthetic MgO, which were chosen as basic reference catalysts.