共查询到20条相似文献,搜索用时 15 毫秒
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Luo Laitao Li Songjun Deng Gengfeng Li Fengyi 《Reaction Kinetics and Catalysis Letters》2002,75(2):289-296
The effect of samarium on Ni/sepiolite catalyst was investigated by benzene hydrogenation, methanation of carbon dioxide, CO chemisorption, XPS and CS2 poisoning, respectively. The result indicates that a proper amount and impregnation order of samarium in the preparation of Ni-Sm/sepiolite catalyst are very efficient to improve the catalytic activity and anti-sulfur ability. At the same time, the mechanism of samarium improving hydrogenation activity of Ni/sepiolite is presented. 相似文献
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随着全球能源消耗的不断增长和环境污染问题的日益严重,寻找清洁、高效的CO2利用路径成为研究热点。甲醇由于用途广泛,既是重要的化工原料,也是一种新型清洁能源。CO2催化加氢制甲醇过程不仅实现CO2减排,还是碳资源循环利用的有效途径之一,对解决能源紧缺和环境问题具有重要意义。高活性、高选择性和高稳定性的CO2加氢制甲醇催化剂的开发一直是该过程的核心技术。本文综述了二氧化碳加氢制甲醇的研究进展,主要介绍了反应机理和催化剂,并以Cu基催化剂重点总结了活性位、载体和助剂对催化性能的影响,最后对二氧化碳加氢制甲醇的应用前景进行了展望。 相似文献
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采用密度泛函理论(DFT)对锰配合物催化二氧化碳加氢生成甲酸的反应进行了理论研究. 整个催化循环主要包括氢气活化和二氧化碳氢化2个阶段. 计算结果表明, 甲酸的参与明显降低了氢气活化的反应能垒; 二氧化碳的氢化过程遵循外层机理并且氢转移是分步进行的, 决速步骤为氢负离子的转移过程, 自由能垒为21.0 kJ/mol. 对配合物中硫原子上的取代基R进行了调变, 研究结果表明, 当R为吸电子基团时能降低氢气裂解和二氧化碳氢化过程中质子转移的能垒, 而当R为推电子基团时有利于氢负离子的转移,当R=CF3时整个反应的能量跨度(80.4 kJ/mol)最小. 相似文献
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Hydrogen reduction of a Pd(II)-beta-diketone precursor in supercritical carbon dioxide produces palladium nanoparticles on multi-walled carbon nanotubes that exhibit promising catalytic properties for hydrogenation of olefins in carbon dioxide as well as electro-reduction of oxygen in fuel cell applications. 相似文献
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Development of a Ruthenium/Phosphite Catalyst System for Domino Hydroformylation–Reduction of Olefins with Carbon Dioxide
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Dr. Qiang Liu Lipeng Wu Dr. Ivana Fleischer Dr. Detlef Selent Prof. Dr. Robert Franke Dr. Ralf Jackstell Prof. Dr. Matthias Beller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(23):6888-6894
An efficient domino ruthenium‐catalyzed reverse water‐gas‐shift (RWGS)‐hydroformylation‐reduction reaction of olefins to alcohols is reported. Key to success is the use of specific bulky phosphite ligands and triruthenium dodecacarbonyl as the catalyst. Compared to the known ruthenium/chloride system, the new catalyst allows for a more efficient hydrohydroxymethylation of terminal and internal olefins with carbon dioxide at lower temperature. Unwanted hydrogenation of the substrate is prevented. Preliminary mechanism investigations uncovered the homogeneous nature of the active catalyst and the influence of the ligand and additive in individual steps of the reaction sequence. 相似文献
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Methane reforming by carbon dioxide has been studied over ultra-stable Ni catalysts. The catalyst was characterized by XRD, IR and TEM and temperature programmed hydrogenation. The nickel–magnesia solid solution catalyst containing low nickel has shown excellent stability (>3000 h) and no carbon deposition in the methane reforming by carbon dioxide. It was also found that the small nickel metal particle interaction with support surface is effective for the inhibition of carbon formation. 相似文献
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V. I. Vigdorovich S. E. Sinyutina L. E. Tsygankova V. I. Kichigin 《Russian Journal of Applied Chemistry》2006,79(5):761-768
Impedance spectroscopy was used to study the protective action of salts of higher aliphatic oxyethylated amines as universal inhibitors of the hydrogen sulfide and carbon dioxide corrosion and hydrogenation of carbon steel. 相似文献
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A charcoal-supported rhodium catalyst was highly active for the ring hydrogenation of phenol and cresols under supercritical carbon dioxide. 相似文献
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在340 ℃,5.0 MPa条件下,研究了Fe-Zn-M/HY(M=Cr、Al)复合催化剂上CO2的加氢性能。考察了催化剂中Fe含量对CO2转化率、烃类产物及异构烷烃选择性的影响, 并用CO2-TPD、H2-TPR研究了Fe-Zn-M对CO2的吸附和对H2的还原性能。结果表明, 随着Fe含量的增加, 复合催化剂的活性增强, 烃类产物的选择性降低, 异构烷烃在烃类中的选择性随Fe含量的增加而降低,CO2-TPD、H2-TPR结果表明,随Fe含量的增加,催化剂对CO2的活化吸附量随之增加, 而Fe含量的增加促进了催化剂的还原。 相似文献
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Langer R Diskin-Posner Y Leitus G Shimon LJ Ben-David Y Milstein D 《Angewandte Chemie (International ed. in English)》2011,50(42):9948-9952
A highly active iron catalyst for the hydrogenation of carbon dioxide and bicarbonates works under remarkably low pressures and achieves activities similar to some of the best noble metal catalysts. A mechanism is proposed involving the direct attack of an iron trans-dihydride on carbon dioxide, followed by ligand exchange and dihydrogen coordination. 相似文献
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Micelle-hosted palladium nanoparticles catalyze citral molecule hydrogenation in supercritical carbon dioxide 总被引:2,自引:0,他引:2
A new approach of employing metal particles in micelles for the hydrogenation of organic molecules in the presence of fluorinated surfactant and water in supercritical carbon dioxide has very recently been introduced. This is allegedly to deliver many advantages for carrying out catalysis including the use of supercritical carbon dioxide (scCO2) as a greener solvent. Following this preliminary account, the present work aims to provide direct visual evidence on the formation of metal microemulsions and to investigate whether metal located in the soft micellar assemblies could affect reaction selectivity. Synthesis of Pd nanoparticles in perfluorohydrocarboxylate anionic micelles in scCO2 is therefore carried out in a stainless steel batch reactor at 40 degrees C and in a 150 bar CO2/H2 mixture. Homogeneous dispersion of the microemulsion containing Pd nanoparticles in scCO2 is observed through a sapphire window reactor at W0 ratios (molar water-to-surfactant ratios) ranging from 2 to 30. It is also evidenced that the use of micelle assemblies as new metal catalyst nanocarriers could indeed exert a great influence on product selectivity. The hydrogenation of a citral molecule that contains three reducible groups (aldehyde, double bonds at the 2,3-position and the 6,7-position) is studied. An unusually high selectivity toward citronellal (a high regioselectivity toward the reduction of the 2,3-unsaturation) is observed in supercritical carbon dioxide. On the other hand, when the catalysis is carried out in the conventional liquid or vapor phase over the same reaction time, total hydrogenation of the two double bonds is achieved. It is thought that the high kinetic reluctance for double bond hydrogenation of the citral molecule at the hydrophobic end (the 6,7-position) is due to the unique micelle environment that is in close proximity to the metal surface in supercritical carbon dioxide that guides a head-on attack of the molecule toward the core metal particle. 相似文献
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铁钴双金属催化剂上二氧化碳加氢合成低碳烯烃 总被引:9,自引:0,他引:9
研究了常压下铁钴双金属催化剂上二氧化碳催化加氢合成低碳烯烃的反应,考察了钴含量、反应温度对二氧化碳转化率、产物选择性的影响。结果表明,钴的添加有利于铁的碳化,提高了二氧化碳转化率,降低了一氧化碳选择性,提高了甲烷选择性,适量钴的添加促进了二氧化碳向烃的转化。在铁钴摩尔比67∶33,反应温度350℃,反应空速5000mlg-1h-1条件下,二氧化碳转化率达到281%,C+2选择性达到116%,烯烷比5 相似文献
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Hiyoshi N Sato O Yamaguchi A Shirai M 《Chemical communications (Cambridge, England)》2011,47(41):11546-11548
The addition of carbon dioxide and water enhances acetophenone hydrogenation activity over an activated carbon-supported palladium catalyst, and 1-phenylethanol can be easily recovered without distillation and neutralization. Two liquid phases (water and acetophenone) are indispensable for enhancement of the hydrogenation rate. 相似文献