Ketonization of carboxylic acids over CeO2-based composite oxides
Ketonization of carboxylic acids over CeO2-based composite oxides
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DOI：
10.1016/j.molcata.2004.10.042
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发表时间：
2005-03-01
影响因子：
--
通讯作者：
Sodesawa, T
中科院分区：
文献类型：
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作者：
Nagashima, O;Sato, S;Sodesawa, T
研究了CeO_2基复合氧化物催化丙酸酮化合成3-戊酮的反应。CeO 2基固溶体CeO 2-Mn 2 O3对酮化反应是有效的。柠檬酸盐法是制备分散良好的固溶体的最合适的方法。在丙酸与另一种线性羧酸的酮化反应中，形成了一个不对称酮和两个对称酮，酮的组成近似于二项分布。羧酸的反应性随着其链长的增加而略微降低。与直链脂肪酸相比，支链酸的反应性较低。在羧酸的α-和β-位上的甲基取代基降低了它们在均酮化和交叉酮化中的反应活性。据推测，α-氢的缺乏或空间位阻的增加是反应性降低的原因。(C)2004 Elsevier B. V.保留所有权利。
The ketonization of propanoic acid to form 3-pentanone over CeO2-based composite oxides at temperatures of 300-425 degreesC was investigated. A CeO2-based solid solution, CeO2-Mn2O3, was effective for the ketonization. The citrate process was the most appropriate method for preparing, a well-dispersed solid solution. In the ketonization of propanoic acid with another linear carboxylic acid, an asymmetric ketone together with two symmetric ketones was formed, and the ketone composition was approximated by a binomial distribution. The reactivity of the carboxylic acid was slightly decreased as its chain length was increased. In contrast to linear aliphatic acids, branched acids were less reactive. Methyl group substituents at the alpha- and beta-positions of carboxylic acids decreased their reactivities in both homo- and cross-ketonization. The lack of an alpha-hydrogen or the increase in steric hindrance was surmised to be the cause of the decrease in reactivity. (C) 2004 Elsevier B.V. All rights reserved.