【作者】 李志强；

【导师】 李光兴；

【作者基本信息】 华中科技大学 ， 物理化学， 2007， 硕士

【摘要】 均相催化剂虽然活性高但往往难以分离且有腐蚀性,而多相催化剂则易于分离、再生和回收使用,因此将均相催化剂进行负载化可使催化剂兼具均相与多相催化剂的优点。有机-无机杂化材料（Organic inorganic hybrid, OIH）既含有机成分又含无机成分,用作催化剂载体时,既利用了有机部分的活性位又利用了无机部分回收催化剂,具有重大的理论意义和很好的应用潜力;溶胶-凝胶（Sol-gel）技术在制备OIH方面具有很多优点,比如热稳定性好、呈化学惰性、具有高比表面和孔隙率等,因此溶胶-凝胶技术制备负载催化剂是一种很有发展前途的方法。本文首先研究了以γ-氨丙基三乙氧基硅烷（APTES）作偶联剂,2-乙酰基吡啶作有机改性配体,二者反应生成含有可水解基团-OEt的中间体,该产物与正硅酸乙酯（TEOS）通过溶胶-凝胶（Sol-gel）过程形成具有SiO2网络结构的OIH,进而与CuCl反应生成负载催化剂CuCl/OIH（A）。其次,以γ-氯丙基三乙氧基硅烷（CPTES）作偶联剂,5-氨基-1,10-菲罗啉（5-NH2-1,10-Phen）作有机配体,TEOS作硅源,采用Sol-gel法合成无定形OIH,并与CuCl反应生成负载催化剂CuCl/OIH（B）。探讨了反应温度、反应时间、原料配比、合成路线等因素对催化剂合成的影响,得出仲胺Phen-NH-（CH2）3-Si（OEt）3的最佳合成条件为:溶剂N,N-二甲基甲酰胺（DMF）,NH₂-Phen用量10 mg/ml,CPTES:NH2-Phen=1.1:1（摩尔比）,反应温度70℃,反应时间72 h。采用元素分析（EA）、傅立叶变换红外光谱（FT-IR）、热重分析（TGA）、差热分析（DTA）、核磁共振(¹HNMR, ²⁹Si-MAS-NMR)等分析手段对两种负载催化剂CuCl/OIH（A）和CuCl/OIH（B）及合成中间产物进行了表征,并采用火焰原子吸收光谱（AAS）测定了负载催化剂的铜负载量。第三,分别考察了两种负载催化剂用于甲醇氧化羰化合成碳酸二甲酯（DMC）反应的催化性能,并对负载催化剂与均相催化体系的催化活性进行了比较。在120℃,反应总压2.4 MPa,P_CO:P_O2=2:1,CCu=0.1 mol/L,反应时间2 h的条件下,使用负载催化剂CuCl/OIH（B）与CuCl单独作催化剂相比,DMC产率提高了25.0 %,负载催化剂循环使用四次,DMC选择性和产率基本保持不变。采用AAS测得催化剂活性中心铜平均流失仅为2.3 wt%,表明CuCl与载体键合牢固。更多还原

【Abstract】 Homogeneous catalytic systems often have disadvantages, such as difficult separation from the products and corrosive effect on the reactor materials. Heterogeneous catalytic systems have attractive advantages over homogeneous counterparts in liquid-phase reactions, including easy removal of catalysts from reaction mixtures and recycling of catalysts. Organic-inorganic hybrid materials （OIH）, in which the organic groups are covalently attached to porous inorganic solids, can be used as catalyst support. The goal in this paper is to utilize the organic moiety as the active site and the inorganic solid to provide avenues for recovering the active site. This new kind of catalyst system is expected to contribute to the development of commercialization of homogeneous catalytic reactions. The Sol-gel technology offers several advantages employed in the preparation of heterogeneous catalysts. Inorganic Sol-gel supports are indeed superior in their thermal stability, inertness towards molecules, and in their porosity and high surface areas. Thus, the Sol-gel technology is a promising method using to synthesize the supported catalyst.Firstly, OIH was prepared by Sol-gel technique usingγ-aminopropyltriethoxysilane （APTES） as spacer, 2-acetylpyridine as organic ligand, and tetraethoxysilane （TEOS） as precursor, then the OIH was reacted with CuCl to prepare heterogeneous catalyst CuCl/OIH （A）.Secondly, cuprous chloride catalysts CuCl/OIH （B） anchored on silica-based support were synthesized by Sol-gel technique usingγ-chloropropyltriethoxysilane （CPTES） as spacer, 5-amino-1,10-phenanthroline as organic ligands and TEOS as precursor. The effects of reaction temperature, reaction time and other factors on the synthesis of OIH were investigated. The results show that the optimum reaction conditions for synthesis of secondary ammonia are: the solvent DMF, the concentration of NH2-Phen 10 mg/ml, molar ratio of CPTES to NH₂-Phen 1.1:1, reaction temperature 70℃,reaction time 72 h. The structure of support and heterogeneous catalyst were characterized by EA, FT-IR, TGA, DTA and NMR (¹H NMR, ²⁹Si-MAS-NMR). The copper loading of the supported catalyst were detected by atomic absorption （AAS）. Thirdly, the catalytic activity of CuCl/OIH in the oxidative carbonylation of methanol to dimethyl carbonate was studied in this paper. The catalyst CuCl/OIH （B） exhibited higher activity and selectivity than the homogeneous CuCl catalysts, the yield of dimethyl carbonate improved 25.0 %. It could be separated easily and reused several times, with slight loss of the active components. After recycling 4 times, the catalyst still showed high catalytic activity and selectivity under the reaction conditions of [Cu（I）]=0.1 mol/L, 2.4 MPa (P_CO:P_O2=2:1), 2 h, 120℃.更多还原