Copper Bis(oxazoline) Encapsulated in Zeolites and Its Application as Heterogeneous Catalysts for the Cyclopropanation of Styrene

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• 作者：Ana Rosa Silva ; H茅lio Albuquerque ; Andr茅 Fontes ; Susana Borges ; 脗ngela Martins ; Ana Paula Carvalho ; Jo茫o Pires
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2011
• 出版时间：October 19, 2011
• 年：2011
• 卷：50
• 期：20
• 页码：11495-11501
• 全文大小：882K
• 年卷期：v.50,no.20(October 19, 2011)
• ISSN：1520-5045

文摘

A copper C₂-symmetric bis(oxazoline), CuBox, was introduced in two forms of commercial Y zeolite: a sodium form (NaY) and an ultrastable form (NaUSY). CuBox was introduced by first partially exchanging the sodium cations of both zeolites for copper and then by refluxing the obtained materials with a solution of bis(oxazoline) (Box). Two different loadings were prepared for each form of zeolite. The materials were characterized by copper ICP-AES, elemental analysis, XPS, FTIR, TG, and nitrogen adsorption isotherms at 鈭?96 掳C. Evidence for Box ligand location in the supercages of NaY and NaUSY zeolites and its coordination to the exchanged copper(II) was obtained by the several techniques used. The materials were all active in the cyclopropanation of styrene with ethyldiazoacetate at room temperature and diastereoselective toward trans cyclopropanes. Although the materials containing Box showed low enantioselectivities, their catalytic activities were higher than the parent copper exchanged zeolites, and did not decrease with reuse, at least during three consecutive cycles.