Effect of Triton X-100 additive on the synthesis of Beta zeolites and their catalytic application in acylation of anisole with acetic anhydride

Abstract

A common nonionic surfactant of Triton X-100 (TX) was used as an additive in the hydrothermal synthesis of Beta zeolites (Beta-nTX, n represents the molar ratio of TX/SiO2). The effect of the addition amount of TX on the crystallization process of Beta zeolites was investigated by combining a variety of characterization means. Introducing a small amount of TX (e.g., n = 0.005) in the initial sol-gel system could considerably shorten the induction period of crystallization, thus effectively improving the crystallization rate of Beta zeolites. Moreover, the crystal size of the resultant Beta zeolites decreases obviously after introducing the TX additive. The H-form Beta-nTX zeolites showed much higher catalytic activity in the acylation of anisole with acetic anhydride than the conventional Beta zeolite. Their excellent catalytic performance should be mainly related to the relatively small particle size and high crystallinity of Beta-nTX zeolites, which can reduce the diffusion limitation and improve the accessibility of catalytically active acid sites to reagents.