2000 Fiscal Year Final Research Report Summary
Development of the Sulfide-Based Catalysts for the CO Hydrogenation Reaction in the Presence of H_2S
| Project/Area Number |
10450298
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
触媒・化学プロセス
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| Research Institution | Tohoku University |
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Principal Investigator |
YAMADA Muneyoshi Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (40091764)
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| Co-Investigator(Kenkyū-buntansha) |
KOIZUMI Naoto Tohoku University, Graduate School of Engineering, Research Associate, 大学院・工学研究科, 助手 (50302188)
OMATA Kouji Tohoku University, Graduate School of Engineering, Assistant Professor, 大学院・工学研究科, 助教授 (70185669)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Synthesis gas / Higher alcohol synthesis / Mo sulfide / Sulfur tolerance / Coordinative unsaturation / FTIR spectroscopy / EXAFS spectroscopy / High surface area |
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| Research Abstract |
Synthesis of higher alcohol from CO+H_2 (syngas) on alkali metal-promoted MoS_2 catalysts has been studied because of their advantages of a sulfur tolerance. However, the activity for the synthesis of the higher alcohol of these catalysts is lower than those of the Cu/Zn based catalysts. Besides, the chain growth probability of the formed alcohol lies in the range from 0.2 to 0.25, which indicates that the alcohol is mainly composed of methanol. The present work tried to make clear factors in determining the activity and selectivity for the CO hydrogenation reaction of the alkali metal-promoted MoS_2 catalysts. Based on the results, we developed a novel preparation method for the catalysts which show the higher activity and selectivity for the synthesis of the higher alcohol.
MoS_2-based catalysts are widely used for the hydrotreating reaction of the oil fractions. It is suggested that sulfur-vacant sites are formed on the sulfides under the reducing conditions and are involved in the r
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eaction. In the case of the CO hydrogenation reaction on the MoS_2-based catalysts, however, the role of the sulfur vacant sites has not been made clear yet. The present work found that the selectivity for C_2-C_3 alcohol of K-MoS_2/Al_2O_3 increased with increasing the time on-stream, which accompanies the desorption of H_2S.In-situ FTIR spectroscopy coupled with the adsorption of NO probe molecule showed that the surface fine structure of the catalyst changed by the desorption of H_2S.By combining the results obtained by FTIR spectroscopy with those by EXAFS spectroscopy, it was suggested that the coordinatively unsaturated K sites and the coordinatively unsaturated Mo sites interacted with K species were formed under the reaction conditions. It was also suggested that the surface fine structure of the catalyst changed dynamically depending on the concentration of the gas-phase H_2S.
To increase the number of the interaction species between K and Mo species as was suggested by FTIR and EXAFS spectroscopy, the present work tried to spread the alkali metal species uniformly over the surface of MoS_2 having the high surface area. The developed catalyst showed the higher activity for the synthesis of C_2-C_4 alcohol with the higher chain growth probability than the conventional (low surface area) catalyst. Less
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Research Products
(2 results)
