Modified Beta Zeolite as Catalyst for Fries Rearrangement Reaction

Abstract

Modified beta zeolites were applied as catalysts for the Fries rearrangement reaction. The properties of the modified zeolites were characterized by NH3-TPD, n-hexane and 1,2,4-trimethylbenzene adsorption. Modification with SiO2 did not block the pores of the beta zeolite but reduced the number of acid sites on the surface. However, when the beta zeolite was modified with Ce2O3, the number of acid sites determined by NH3-TPD increased, which indicated that new acid sites are created by the interaction of cerium oxide and zeolite. Modified beta zeolites and H-beta were applied as catalysts for the Fries rearrangement of phenol acetate. Reaction over H-beta has low selectivity and the catalyst is easily deactivated. SiO2 modification of the catalyst increases the selectivity of the reaction but decreases the conversion. Ce2O3-modified beta zeolites show higher catalytic activity and rearrangement selectivity in the reaction than other catalysts. The stability of the catalyst is also improved after Ce2O3 modification. About 70% selectivity and 60-80% conversion can be achieved over 16 wt% Ce2O3-modified beta zeolite.