含氨基酸侧链的有机硅高分子催化剂——Ⅹ.聚γ-(酪氨酸基)丙基硅氧烷钯催化剂的合成、加氢活性及结构表征  

STUDY OF POLYSILOXANE WITH AMINO -ACID SIDE CHAIN SUPPORTED CATALYSTS X. THE SYNTHESIS, HYDROGENATION ACTIVITY AND STRUCTURAL CHARACTERIZATION OF POLY-v-CTYROSINE) PROPYLSILOXANE PALLADIUM CATALYSTS

作　　者：刘基万[1] 游江[1] 王西新[1] 

机构地区：[1]武汉大学化学系,武汉430072

出　　处：《分子催化》1991年第2期154-159,共6页Journal of Molecular Catalysis(China)

基　　金：国家自然科学基金

摘　　要：本文报导了四种不同N/Pd摩尔比的聚γ-(酪氨酸基)丙基硅氧烷钯催化剂的合成。催化剂的结构表征结果指出,其活性中心的组成可能是酪氨酸配体中的N和PdCl_2络合。这种催化剂对实验底物都有很高的加氢活性;当N/Pd摩尔比为2时,催化剂的加氢活性最佳;溶剂对催化剂的活性有显著影响;催化剂在pH值为5.5～7.0的反应体系中使用较为适宜。We have reported the synthesis of some supported catalysts of polysiloxane with amino-acid side chain and their catalytic activity for the hydrogenation of olefins and nitrobenzene recently. This paper is concerned with the synthesis of poly-γ- ( tyrosine) propylsiloxane palladium catalysts with different N/Pd mol ratios and its catalytic hydrogenation activity. Polymer-palladium complexes prepared from PdCl2 and poly-γ-(tyrosine) propylsiloxane supported on fumed silica were described. The hydrogenatian reaction, was carried out in a reactor with magnetic stirrer under a constant supply of hydrogen and the volumes of hydrogen absorption were measured. The products were analyzed by gas chromatograph. The structural characterization of catalyst was accomplishld by XPS and FT-IR. The data of the differential IR spectra indicated that the polysil-oxane with tyrosine side chain as ligand was formed. XPS analysis was used to characterize the surface structure of the catalysts and the changes in valence state of atoms involved. The observation showed that the active center may be the complex compound composed of the nitrogen of tyrosine ligand and Pd atoms in PdCl2. Besides, palladium in the catalysts exists in the form of Pd ( 0 ) and Pd ( Ⅱ ) . For a lot of substrates, the hydrogenation activity of the title complexes is high. The initial hydrogen absorption rate of acrylonitr-ile is up to 2207 ml/min·mmol Pd on the catalyst with the N/Pd ratio of 2.0. The catalytic activity is greatly affected by the N/Pd mol ratio in the catalysts. The influence of solvents on the hydrogenation activity of acrylo-nitrile is markable and the initial hydrogen absorption rate is the highest in anhydrous ethanol, but the hydrogenation reaction did not take place in i-PrOH and n-hexane. The use of the title catalyst is appropriate in the reaction system with pH 5.5-7.0. The rate of hydrogen absorption increased with increasing temperature and reached a maximum at 40 ℃. Furthermore, th

关 键 词：有机硅 高分子 催化剂 氨基酸 

分 类 号：TQ426.7[化学工程]