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Study on catalysts for higher hydrocarbon and aromatics formation from small alkane molecules

小分子烷烃生成高级烃和芳烃的催化剂研究

基本信息

批准号：
10650775
负责人：
NAITO Shuichi
金额：
$ 0.58万
依托单位：
Kanagawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

In this research project, we have tried to develop new catalysts, which can covert small alkane molecules such as methane, ethane and propane into higher hydrocarbons or aromatic compounds. First of all, we have investigated CHィイD24ィエD2-CO reaction over silica supported group VIII metal catalysts using closed gas circulation system, and found that benzene is formed selectively among hydrocarbons. Dependence of the initial rates of CHィイD24ィエD2-CO reactions as well as CHィイD24ィエD2 coupling and CO disproportionation upon the particle sizes of Rh was investigated by changing the loading amount of Rh on silica. The TOFs for benzene formation in CHィイD24ィエD2-CO reaction and CィイD22ィエD2 formation in CHィイD24ィエD2 coupling were increased abruptly by decreasing the loading amount of Rh. On the contrary, the TOF of COィイD22ィエD2 formation by CO disproportionation was decreased by decreasing the loading. These results suggest that smaller Rh particle may enhance the dissociation of methane C-H bond to supply surface hydrogen for benzene formation. We have also investigated the addition effect of rear-earth oxides to Rh/SiOィイD22ィエD2 catalysts, and found that NdィイD22ィエD2OィイD23ィエD2 is the effective additives for benzene acceleration for more than ten times.On the other hand, we have constructed conventional flow reactor system and studied the methane coupling reaction over molybdenum carbides as well as supported group VIII metal catalysts. In the case of MoィイD22ィエD2C catalysts, benzene can be formed with the 10-20% conversions and about 60% selectivity. In the cases of silica supported Co, Ni, Ru, Pd, Os, Ir and Pt catalysts, small amount of benzene was detected over Rh/SiOィイD22ィエD2, Ir/SiOィイD22ィエD2 and Pt/SiOィイD22ィエD2 catalysts. However, the deactivation of the catalytic activity was so severe in any catalysts maybe because of the carbon accumulation. Further improvement of the catalytic systems are required for practical use of these catalysts.

在本研究项目中，我们试图开发新的催化剂，可以将小烷烃分子如甲烷、乙烷和丙烷转化为高级烃或芳香族化合物。首先，我们研究了在二氧化硅负载的第VIII族金属催化剂上，使用封闭气体循环系统的CH_（24）CH_（24）CH_（24）D_2-CO反应，发现苯在烃中选择性地生成。通过改变Rh在SiO_2上的负载量，研究了CH_（24）CH_（24）CH_（24）CH_（24）D_2-CO反应、CH_（24）CH_（24）CH_（24）D_2偶联反应和CO还原反应的初始速率与Rh粒径的关系。随着Rh负载量的降低，CH_（24）CH_（22）CH_（24）CH_（相反，通过CO反硝化形成CO反硝化D22反硝化D2的TOF随着负载量的降低而降低。这些结果表明，较小的Rh颗粒可能会促进甲烷C-H键的解离，为苯的生成提供表面氢。本文还考察了稀土氧化物对Rh/SiO_（22）O_（23）在Mo催化剂的情况下，可以以10-20%的转化率和约60%的选择性形成苯。在SiO2负载的Co、Ni、Ru、Pd、Os、Ir和Pt催化剂上，Rh/SiO2-D22-D2、Ir/SiO2-D22-D2和Pt/SiO2-D22-D2催化剂上检测到少量的苯。然而，在任何催化剂中，催化活性的失活如此严重可能是由于积碳。为了实际应用这些催化剂，需要进一步改进催化体系。