Abstract

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.

中文翻译：

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合成方法对BEA沸石理化和催化性能的影响

摘要

_{本研究研究了在氟化物和碱性介质中合成的SiO 2} /Al ₂ O ₃比为50～250的BEA沸石的物理化学性质，并测试了它们在液相条件下苯与丙烯烷基化的催化活性。_{通过氟化物路线合成的SiO 2} /Al ₂ O ₃比率相似的样品表现出较大的晶体尺寸和较少的晶体缺陷。无论合成介质如何，含有 SiO ₂ /Al ₂ O _3的样品= 50 证明在苯与丙烯的烷基化中比沸石骨架中铝含量较低的样品更活跃和更稳定。通过氟化物路线制备的样品实现了更高的异丙苯选择性。这可以通过它们的外表面积低于在碱性介质中制备的沸石来解释，在碱性介质中，副反应会产生大分子的二和三异丙基苯。