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Preparation of Nickel Catalyst Supported on Ultra Fine Titania Particles

超细二氧化钛颗粒负载镍催化剂的制备

基本信息

批准号：
63550724
负责人：
TAKAHASHI Takeshige
金额：
$ 1.15万
依托单位：
Faculty of Engineering, Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

The preparation of ultra fine titania particles was carried out by the decomposition of titanium tetraisopropoxide(TTIP) in gas phase. The mean diameter and surface area of the particles were strongly dependent upon the preparation conditions, that is, high temperature, high TTIP concentration and long residence time in a reactor resulted in large particle size and small surface area. The smallest size of titania particle was around 15 nm and it was almost coincided the value calculated from the surface area, measured from nitrogen adsorption method. The result indicated that the surface area was regarded as outer surface area and the particles did not have a micro pore.The nickel catalyst supported on the ultra fine particles was prepared with impregnation method and CVD method. Furthermore, the gas phase hydrogenation of benzene was carried out over the nickel catalysts. The hydrogenation activity was proportional to the surface area of the ultra fine titania, even though the catalys … More t had the same nickel contents. The result suggested that nickel was well dispersed on the titania with large surface area. Although the nickel content of the catalyst prepared by CVD method was lower than that of impregnated ca talyst, the turn over frequency of the former was larger than that of the latter. This result implied that nickel catalyst with high dispersion could be prepared by a CVD method.The hydrogenation of methyl oleate was carried out in a batch reactor at an atmospheric pressure. The nickel catalysts prepared by the impregnation method and CVD method were dispersed in the solution contained methyl oleate, and hydrogen with constant flow rate was supplied in the solution. The catalytic activity and selectivity to methyl stearate were examined over the catalysts. The selectivity over the catalyst prepared by CVD method was higher than that over the catalyst prepared from impregnation method. However, the reaction was carried out over the catalyst supported on alumina with large pore volume, the selectivity to methyl stearate significantly decreased. Furthermore, the catalytic deactivation of alumina supported catalyst was larger than that supported on the titania prepared from the CVD method. It was considered that the further decomposition over nickel active sites in the micro pore on the alumina would decrease the selectivity.The ultra fine titania particles prepared by the CVD method was useful as a catalyst support for the reaction with large heat of reaction Less

采用四异丙醇钛（TTIP）气相分解法制备超细二氧化钛颗粒。颗粒的平均直径和表面积很大程度上取决于制备条件，即高温、高TTIP浓度和在反应器中的长停留时间导致颗粒尺寸大和表面积小。二氧化钛颗粒的最小尺寸约为15 nm，与氮吸附法测量的表面积计算值几乎一致。结果表明，表面积视为外表面积，颗粒不具有微孔。采用浸渍法和CVD法制备了超细颗粒负载镍催化剂。此外，苯的气相加氢反应是在镍催化剂上进行的。即使催化剂具有相同的镍含量，氢化活性也与超细二氧化钛的表面积成正比。结果表明，镍在具有大表面积的二氧化钛上分散良好。虽然CVD法制备的催化剂镍含量低于浸渍催化剂，但前者的周转频率高于后者。这一结果表明可以通过CVD法制备高分散性的镍催化剂。油酸甲酯的加氢反应在间歇式反应器中在常压下进行。将浸渍法和CVD法制备的镍催化剂分散在含有油酸甲酯的溶液中，并以恒定流量向溶液中通入氢气。考察了催化剂的催化活性和对硬脂酸甲酯的选择性。 CVD法制备的催化剂的选择性高于浸渍法制备的催化剂。然而，反应在大孔容氧化铝负载催化剂上进行，硬脂酸甲酯的选择性显着下降。此外，氧化铝负载型催化剂的催化失活大于CVD法制备的二氧化钛负载型催化剂。认为氧化铝微孔中镍活性位点的进一步分解会降低选择性。CVD法制备的超细二氧化钛颗粒可用作反应热较大的反应的催化剂载体。