Synthesis of Itaconic Acid Ester Analogues via Self-Aldol Condensation of Ethyl Pyruvate Catalyzed by Hafnium BEA Zeolites

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• 作者：Yuran Wang ; Jennifer D. Lewis ; Yuriy Román-Leshkov
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：May 6, 2016
• 年：2016
• 卷：6
• 期：5
• 页码：2739-2744
• 全文大小：344K
• 年卷期：0
• ISSN：2155-5435

文摘

Lewis acidic zeolites are used to synthesize unsaturated dicarboxylic acid esters via aldol condensation of keto esters. Hafnium-containing BEA (Hf-BEA) zeolites catalyze the condensation of ethyl pyruvate into diethyl 2-methyl-4-oxopent-2-enedioate and diethyl 2-methylene-4-oxopentanedioate (an itaconic acid ester analogue) with a selectivity of ca. 80% at ca. 60% conversion in a packed-bed reactor. The catalyst is stable for 132 h on stream, reaching a turnover number of 5110 mol_EP mol_Hf^–1. Analysis of the dynamic behavior of Hf-BEA under flow conditions and studies with Na-exchanged zeolites suggest that Hf(IV) open sites possess dual functionality for Lewis and Brønsted acid catalysis.