Silica-Supported Heteropoly Acid Catalyst for Liquid-Phase Friedel–Crafts Reactions
Silica-Supported Heteropoly Acid Catalyst for Liquid-Phase Friedel–Crafts Reactions
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用于液相傅克反应的二氧化硅负载杂多酸催化剂
DOI：
10.1246/bcsj.62.2159
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发表时间：
1989
影响因子：
4
通讯作者：
K. Urabe
中科院分区：
文献类型：
--
作者：
Y. Izumi;N. Natsume;Harumi Takamine;Ikuyo Tamaoki;K. Urabe
二氧化硅负载的Keggin杂多酸，如12-钨磷酸、钼磷杂多酸和钨硅杂多酸，有效地催化了芳香烃与1-辛烯、苯氯和苯甲酰氯在液相中的Friedel-Craft烷基化和酰化反应。负载在二氧化硅上的杂多酸的催化活性普遍提高。二氧化硅负载的钨硅酸即使在对二甲苯与苯甲酰氯或苯甲酸酐的酰化反应中也能起到不溶于水的多相催化剂的作用，尽管重复使用会出现失活现象。考虑到负载型对甲苯磺酸是一种常用的典型的强质子酸，其催化活性远低于负载型杂多酸，杂多酸的高催化效率似乎是由于杂多阴离子的独特性质，它可以稳定烷基和酰基阳离子作为反应中间体。
Silica-supported Keggin-type heteropoly acids such as 12-tungstophosphoric, molybdophosphoric, and tungstosilicic acids efficiently catalyzed Friedel–Crafts alkylation and acylation reactions of aromatic hydrocarbons with 1-octene, benzyl chloride and benzoyl chloride in the liquid phase. The catalytic activity of heteropoly acid was generally enhanced when supported on silica. Silica-supported tungstosilicic acid worked as an insoluble heterogeneous catalyst even to the acylation of p-xylene with benzoyl chloride or benzoic anhydride, though deactivation was observed during repeated use. Considering that supported p-toluenesulfonic acid, an ordinarily used typical strong protonic acid, was far less active than the supported heteropoly acid, the high catalytic efficiency revealed by heteropoly acid appears to be due to a unique property of heteropoly anion which can stabilize alkyl and acyl cations as the reaction intermediates.