含氨基酸侧链的有机硅高分子催化剂 ⅩⅤ.γ-(L-酪氨酰胺基)丙基硅氧烷钯催化剂的合成加氢活性及其结构表征  

Study on Polysiloxane with Amino-Acid Side Chain Supported Catalysts XV The Synthesis, Hydrogenation Activity and Structural Characterization of Poly-γ- (L-Tyrosinamido)Propylsiloxane Palladium Catalysts

作　　者：游江[1] 刘基万[1] 毛云中 

机构地区：[1]武汉大学化学系,武汉430072

出　　处：《分子催化》1992年第5期359-364,共6页Journal of Molecular Catalysis(China)

基　　金：国家自然科学基金资助课题

摘　　要：本文报导了四种不同N/Pd摩尔比的聚γ-(L-酪氨酰胺基)丙基硅氧烷钯催化剂的合成及其催化加氢活性,这类催化剂与聚γ-((L-酷氨酸)丙基硅氧烷钯催化剂相比较,虽然均具有类似的N→Pd配位的活性中心组成,但它们对底物的加氢活性则明显不同,前者对丙烯腈、丙烯酸、环己烯和1-癸烯的催化活性比后者高,对苯乙烯则相反。N/Pd摩尔比、反应温度、溶剂以及体系的pH值对催化活性的影响,两者的情况大致相同,标题催化剂对衣康酸的催化加氢,产物的光学纯度为30％。Previous studies on polysiloxane with amino-acid side chain supported palladium catalysts have shown that the small variation in ligand structure caused markedly different hydrogenation activity of the catalyst and the catalyst with the amino- acid C- terminal as the end group exhibited high hydrogenation activity. This paper describes the synthesis of poly-γ-(L-tyrosinamido)propylsiloxane palladium catalysts, the catalyst with the N-terminal as the end group, with different N/Pd molar ratios and their catalytic activity.After reacting the amino group of L-tyrosine with formic acid, the resulting formyl derivative reacted with γ-aminopropyl triethoxy silane in the presence of ethyl chloroformate and triethyl amine to yield γ-(N-formyl-L-tyrosinamido)propyl triethoxy silane, which was supported on fumed silica, followed by acid hydrolysis for removal of the formyl group as the protective group. The obtained polymer supported ligand, poly-γ- (L-tyrosinamido) propylsiloxane, reacted with PdCl2 at various ratios to give the four catalysts tested.XPS data of the tested catalysts indicated that it had the same N→Pd active center as that of poly-γ-(L-tyrosine) propylsiloxane palladium catalyst. However, the catalysts exhibited markedly different initial rates of hydrogen absorption for different substrates, showing higher catalytic activity for acrylonitrile, acrylic acid, cyclohexene, 1-decene, but lower for styrene than the poly-γ-(L-tyrosine) propylsiloxane palladium catalyst.The influence of N/Pd molar ratio, reaction temperature, solvents and of the system pH on catalytic hydrogenation of acrylonitrile were substantially the same for the two types of catalyst. The title catalyst catalyzed asymmetric hydrogenation of itaconic acid to obtain 30% optical yield of the product.

关 键 词：催化剂 酪氨酸 聚硅氧烷 氢化 活性 

分 类 号：O643.361[理学—物理化学]