SYNTHESIS OF NOVEL LAYERED METAL HALIDE OXIDES AND THEIR APPLICATION AS CATALYSTS FOR SELECTIVE ALKANE OXIDATION

(1)金属卤化物氧化物作为固体催化剂的应用为了获得高效、功能化的层状金属卤化物氧化物固体催化剂用于烷烃与分子氧的选择氧化，通过合成各种层状金属卤化物氧化物，包括新结构的样品，积累了关于金属卤化物氧化物的结构、催化活性、选择性、稳定性和卤素的作用等方面的基本信息。铋系卤化物氧化物组成了一大类层状化合物，所有这些化合物都结晶成与四方PbO结构相关的阳离子-氧层片状结构，并与单个或多个卤化物层离子交替。随着卤化物离子多重数的增加，甲烷氧化偶联反应的催化活性和C2烃的选择性显著提高。然而，反之，催化剂的稳定性降低，活性…随着反应时间的延长，催化剂中卤素的释放越多。(2)高分辨电子显微镜和计算机图形学的结构分析新型层状铋系金属氧化物的合成是本工作的关键，因此结构分析非常重要。利用高分辨电子显微镜(HREM)和计算机图形学等手段对层状金属卤化物氧化物催化剂上甲烷氧化偶联反应的动力学进行了研究。根据催化剂本体释放出的卤素物种不参与气相反应的结论，认为催化剂表面的卤化物离子构成了反应的活性中心，它们的反应能力强烈地依赖于与氧片层的相互作用。(4)Arppe相型金属卤化物氧化物的催化性能Arppe‘s pase(M&lt；24&gt；O&lt；31&gt；具有与层状氯氧BiOCl相似结构的单相催化剂，用于甲烷氧化脱氢反应。这些催化剂的稳定性和性能可与上述最好的催化剂相媲美。(5)多金属氧片金属卤化物氧化物的催化性能几种不同类型的铋基氯化物氧化物都具有层状结构，并可调节无限大金属氧片的厚度，作为甲烷氧化的单相催化剂。研究发现，金属氧层之间的氯层是催化性能较高的原因。在此基础上，设计了用于丙烷氧化的高集成度金属卤化物氧化物催化剂。(6)卤化物离子和水在金属卤化物氧化物层间的插层研究发现，在常温下，通过浸泡在金属卤化物水溶液中，卤化物离子和水可以嵌入金属卤化物氧化物的卤化物层间。用X射线衍射仪、EST和EXAFS对该现象进行了表征。不同层状结构的金属氯化物氧化物对叔丁基氯脱氢卤化生成烯烃的催化活性与金属组成和结构有关。较少

(1) Utilization of Metal Halide Oxides as Solid Catalysts In order to obtain highly effective and functionalized solid catalysts based on layred metal halide oxides for selective oxidations of alkanes with molecular oxygen, fundamental informations on the metal halide oxides in terms of structure, catalytic activity, selectivity, stability, and role of halogen, were accumulated by the synthesis of various layred bismuth halide oxides including samples with novel structures. The bismuth-based halide oxides constitute a large family of layred compound, all of which crystallize into structures consisting of cation-oxygen layr sheets associated with the tetragonal PbO structure, alternating with single or multiple sheets of halide ions. As increasing the multiplicity of the halide ion sheet, the catalytic activity for methane oxidative coupling reaction and the selectivity to C_2-hydrocarbons increased prominently. However, reversely decreased the stability of the catalysts, the activities … More deeaying with the reaction time with the liberation of halogen form the catalyst. It was found that these catalysts were also very active and selective for the oxidative dehydrogenation of ethane to ethylene.(2) Structural Analysis with High Resolution Electron Microscopy(HREM) and Computer Graphics The synthesis of novel layred bismuth hallde oxides is a key issue of this work, thus structural analysis being very important. The structural analyzes has been carried out in the aid of high resolution electron microscopy(HREM) and computer graphics.Kinetics of Methane Oxidative Coupling over Layred Metal Halide Oxide Catalysts On the basis that halogen species liberated from the bulk of the catalyst were not involved in the reaction in the gas phase, it is concluded that halide ions on the surface constitute active site for the reaction and their abilities for the reaction strongly depend on the interaction to the oxygen sheet.(4) Catalytic Properties of Arppe's Phase-Type Metal Halide Oxides Three distinet examples of Arppe's pase(M_<24>O_<31>Cl_<10> ; M=Bi, La, Sm), which has a structure related to that of the layred oxychloride BiOCl, have been used as monophasic catalysts for the oxidative dehydrogenation of methane. The stability and performance of these catalysts rival those of the best catalysts previously described.(5) Catalytic Properties of Metal Halide Oxides Having Multiple Metal-Oxygen Sheet Several distinet types of bismuth-based chloride oxides, all of which have layred structures and are regulated on varying the thicknesses of infinite metal oxygen sheets, have been tested as monophasic catalysts for methane oxidation. It was found that the chlorine sheets between the metal oxygen sheets are responsible for the higher catalytic performance. On the basis of this results, highly integrated metal halide oxide catalysts have been designed for propane oxidation.(6) Intercalation of Halide Ion and Water into the Interlayr of Metal Halide Oxides Is was found that halide ion and water can intercalate into the interlayr between halide sheets of metal halide oxides by immersing in aqueous metal halide solution at ambient temperature. The phenomenon was investigated using XRD,EST and EXAFS.Catalytic Activities of Layred Metal Chloride Oxides for Dehydrohalogenation Various metal chloride oxides having layred structure have been tested as catalysts for the dehydrohalogenation of t-butyl chloride to form olefin and were found active for the reaction, depending on the metal constituents and the structure. Less