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Synthesis and Application to Shape Selective Reaction of Microporous Heteropoly Compounds

微孔杂多化合物的合成及其在择形反应中的应用

基本信息

批准号：
07455318
负责人：
OKUHARA Toshio
金额：
$ 3.84万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Recently porous heteropoly compounds were synthesized from H_3PW_<12>O_<40> and Cs^+, and showed shape selective catalysis. Interestingly, the pore dimension of the acidic Cs salts varied from micropores to mesopores by changing the content of Cs. We have studied the catalysis of these porous heteropoly compounds as water tolerant catalysts and shape selective catalysts.Adsorption of various molecules having different molecular size was measured under the relative pressure of 0.2. Cs2.5 and Pt-Cs2.5 adsorbed appreciably all the molecules. However, only N_2 (3.6*) was adsorbed on Pt-Cs2.1 and Pt-Cs2.1, but benzene (5.9*), 2,2-dimethylpropane (6.2*), CCl_4 (6.9*) and 1,3,5-trimethylbenzene (7.5*) were not adsorbed indicating that both Cs2.1 and Pt-Cs2.1 possess the pore widths of 3.6-5.9*. Isotherm of N_2 revealed that Cs2.5 and Pt-Cs2.5 were mesoporous.Hydrolysis of 2-mehtylphenyl acetate was performed at 343K.Cs2.5 was far superior in the activity to other oxide catalysts such as H-ZSM-5, mordenite, SO_4^22-/ZrO_2, Nb_2O_5 and SiO_2-Al_2O_3., showing that Cs2.5 is a promising water-tolerant solid acid. For hydration of 2,3-dimethyl-2-butene, the order of activity (in the unit of catalyst weight) was Cs2.5>H-ZSM-5>>Nb_2O_5-SiO_2-Al_2O_3-SiO_2-TiO_2 (-0). This also support the efficient catalytic function of Cs2.5 as a water-tolerant solid acid.Pt-Csx catalyzed the hydrogenation of alkenes and complete oxidation of alkanes. The activity (per unit weight) for the hydrogenation of ethylene was Pt-Cs2.1 : Pt-Cs2.5=0.5 : 1.0. On the other hand, the activity of Pt-Cs2.1 was less than 1% that of Pt-Cs2.5. Since cyclohexene was not adsorbed on Pt-Cs2.1, this result shows that Pt-Cs2.1 is an efficient shape selective catalyst. Furthermore, Pt-Cs2.1 exhibited shape selectivity for the oxidation of alkanes.

近年来，以H_3PW_O_2和Cs^+为原料合成了多孔杂多化合物<12><40>，并显示出择形催化作用。有趣的是，通过改变Cs的含量，酸性Cs盐的孔尺寸从微孔变为中孔。我们研究了这些多孔杂多化合物作为耐水性催化剂和形状选择性催化剂的催化作用，在相对压力为0.2的条件下测量了不同分子尺寸的各种分子的吸附。Cs2.5和Pt-Cs2.5对所有分子都有吸附作用。而Pt-Cs 2.1和Pt-Cs 2.1只吸附N_2（3.6*），不吸附苯（5.9*）、2，2-二甲基丙烷（6.2*）、四氯化碳（6.9*）和1，3，5-三甲苯（7.5*），表明它们都具有3.6-5.9* 的孔宽。在343 K下催化乙酸2-甲基苯酯水解反应，Cs2.5的活性远高于其它氧化物催化剂如H-ZSM-5、丝光沸石、SO_4 ~（2-）/ZrO_2、Nb_2O_5和SiO_2-Al_2O_3，表现出上级的催化活性。表明Cs2.5是一种很有前途的耐水固体酸。在2，3-二甲基-2-丁烯水合反应中，催化剂的活性顺序（以催化剂重量计）为：Cs 2.5>H-ZSM-5>> Nb_2 O_5-SiO_2-Al_2 O_3-SiO_2-TiO_2（-0）。Pt-Csx催化烯烃的加氢和烷烃的完全氧化。乙烯氢化的活性（每单位重量）为Pt-Cs 2.1：Pt-Cs 2.5=0.5：1.0。另一方面，Pt-Cs2.1的活性小于Pt-Cs2.5的1%。由于环己烯在Pt-Cs 2.1上没有吸附，该结果表明Pt-Cs 2.1是一种有效的择形催化剂。此外，Pt-Cs2.1对烷烃的氧化具有择形性。