Heteropolyacids and large-pore zeolites as catalysts in acylation reactions using α,β-unsaturated organic acids as acylating agents
Heteropolyacids and large-pore zeolites as catalysts in acylation reactions using α,β-unsaturated organic acids as acylating agents
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DOI：
10.1016/s1381-1169(98)00038-7
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发表时间：
1998-09-15
影响因子：
--
通讯作者：
Corma, A
中科院分区：
文献类型：
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作者：
De Castro, C;Primo, J;Corma, A
本文研究了负载于SiO_2上的铯盐形式的磷钨酸（H（3）PW（12）O（40））作为酸催化剂催化甲苯、对二甲苯和间二甲苯与巴豆酸的酰化反应。由于巴豆酸可以烷基化和/或酰化烷基芳族化合物，因此特别选择它来研究催化剂对这两个竞争反应的选择性的影响。当用α，β-不饱和酸酰化时获得的产物的分析表明，所有催化剂对酰化比对烷基化更有活性。发现杂多酸比沸石H-Y和Beta更有活性，即使当考虑每个酸位点的活性时。在杂多酸的情况下，它们的活性与可接近的布朗斯台德酸位点的数量直接相关。(C)1998 Elsevier Science B. V.保留所有权利。
Pure phosphotungstic acid (H(3)PW(12)O(40)), supported on SiO(2), and in the form of Cesium salts have been studied as acid catalysts for the acylation of toluene, p-xylene and m-xylene with crotonic acid. Since crotonic acid can either alkylate and/or acylate the alkylaromatic compounds, it was specifically selected to study the influence of the catalyst on the selectivity for these two competing reactions. Analysis of products obtained when acylating with an alpha,beta-unsaturated acid show that all the catalysts are more active for acylation than for alkylation. Heteropolyacids were found to be more active than zeolites H-Y and Beta, even when the activity per acid site was considered. In the case of heteropolyacids, their activity is directly related to the number of accessible Bronsted acid sites. (C) 1998 Elsevier Science B.V. All rights reserved.