Effects of Synthesis Method on the Physicochemical and Catalytic Properties of BEA Zeolites

This study investigated the physicochemical properties of BEA zeolites with SiO2/Al2O3 ratios of 50 to 250 synthesized in fluoride and alkaline media and tested their catalytic activity in alkylation of benzene with propylene under liquid phase conditions. The samples similar in SiO2/Al2O3 ratio synthesized by the fluoride route exhibited a larger crystal size and fewer crystal defects. Regardless of the synthesis medium, the samples with SiO2/Al2O3 = 50 proved to be more active and stable in alkylation of benzene with propylene than the samples with lower aluminum content in the zeolite framework. The samples prepared by the fluoride route achieved higher cumene selectivity. This can be explained by their lower external surface area than that in the zeolites prepared in alkaline media, where side reactions produce large molecules of di- and triisopropylbenzenes.