共查询到18条相似文献,搜索用时 78 毫秒
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本文综术了杂多化合物作为酸催化剂,催化烷基化和去烷基化反应、缩聚反应、水合和失水、酯化和醚化反应;以及作为氧化催化剂,在烯烃、芳烃、酚的氧化和环氧化反应中的应用。表面杂多化合物作为催化剂在合成精细化学中有广泛的应用价值。 相似文献
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以多孔钛片为支撑体,将组成为HxCu1.2PAs0.6Mo12Oy的杂多化合物与具有氧溢流效应的氧化物Sb2O4制成复合催化膜,在特制的膜催化器中进行异丁烯选择氧化反应,结果表明,杂多化合物-Sb2O4复合催化膜具有较高的催化活性。在适宜的条件下,甲基丙烯酸收率可达26.3%。甲基丙烯醛收率可达22.4%。 相似文献
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Makoto Misono 《Catalysis Reviews》2013,55(2-3):269-321
Heteropolyanions are polymeric oxoanions which are formed by the condensation of more than two different oxoanions [Eq. (1)l. Polyanions consisting of one kind of oxoanion are called isopolyanions [Eq. (2)]. Acidic elements such as Mo, W, V, Nb, and Ta are present as oxoanions in aqueous solutions and polymerize to form polyanions at low pH. Free acids (or acid forms) of these species are called heteropoly and isopoly acids, respectively. Here, the term “heteropoly compounds” is used for heteropoly acids and their salts. 相似文献
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S. V. Khalameida V. V. Sydorchuk J. Skubiszewska-Zięba R. Leboda V. A. Zazhigalov 《Glass Physics and Chemistry》2014,40(1):8-16
Compositions containing heteropoly compounds (ammonium phosphoromolybdate (APM) and phosphoromolybdenum acic (PMA)) are synthesized in a porous silica matrix using the sol-gel method. The obtained compositions containing 5–20 w/w % of APM and PMA are studied with the help of the X-ray-phase and differential-thermal analyses, IR and electron spectroscopy, and nitrogen adsorption. The APM and PMA maintain the Keggin structure after being introduced into an oxide matrix. The samples prepared by the sol-gel method have mesoporous and meso-macroporous structures and enhanced photocatalytic activity in comparison to the initial heteropoly compounds. 相似文献
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杂多化合物作为一类环境友好催化剂,广泛应用于酸催化和氧化-还原催化反应,而杂多化合物的固载方法对催化剂稳定性及活性都有很大影响。本文对近年来国内外杂多化合物的固载方法及应用进行了系统综述,对瓶中造船法、接枝法、孔道包覆法和层间嵌入法等特殊固载方法进行了重点评述。这些用特殊固载方法制备的具有较强主客体相互作用或/和限域作用的负载杂多化合物催化剂各有其特点,适用于不同类型的催化反应。其中,瓶中造船法和孔道包覆法既可保持杂多化合物的酸性和氧化性,又能减少活性组分流失,是制备固载杂多化合物催化剂的理想方法,为研究高稳定性杂多化合物催化剂提供参考。 相似文献
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Makoto Misono 《Korean Journal of Chemical Engineering》1997,14(6):427-431
First, the state of the art of the catalyst design based on heteropoly compounds is briefly overviewed. Then, selected topics
of solid heteropoly catalysts, that is, the selective oxidation of isobutyric acid and isobutane over molybdovanadophosphoric
acids, the methyl t-butyl ether synthesis in pseudoliquid of heteropolyacids, and the shape-selective and bifunctional (combined
with noble metals) acid catalysis of cesium and ammonium salts of tungstophosphoric acid are described based on the recent
studies from our laboratory. 相似文献
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Makoto Misono 《Catalysis Letters》1992,12(1-3):63-71
Characteristics of acid catalysis of solid heteropoly compounds (Keggin-type) have been described, with stress in our study for the design of practical catalysts based on those compounds. 相似文献
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Lacunary tungstophosphoric heteropoly compounds of Keggin structure modified with excess of manganese ions and subsequently calcined at 430-500 °C show high activity and selectivity in oxydehydrogenation of ethane. Steady state ethane conversion is about 25% and selectivity towards ethene 60%. The active catalytic system being a result of reaction between a lacunary heteropoly compound and excess of manganese (II) cations does not show the Keggin structure anymore. 相似文献