| Project/Area Number |
16550008
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical chemistry
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| Research Institution | Chiba University |
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Principal Investigator |
ICHIKUNI Nobuyuki Chiba University, Faculty of Engineering, associate professor, 工学部, 助教授 (40261937)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2005: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2004: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | photo catalyst / molybdenum oxide / mesoporous silica / XAFS / butene metathesis reaction / transmission electron microscopy / photo excitation / X-ray diffraction / ブテン光メタセシス反応 / モリブデン / 1-ブテン光メタセシス反応 / Raman |
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| Research Abstract |
In this research, highly dispersed Mo catalysts supported on mesoporous silica (Mo/MCM-41) were prepared and characterized. The photo-metathesis activity of the catalyst was examined by using 1-butene as reactant. The active center of the photo-catalysis is the metal-carbene species, and hence, the control of the selectivity is difficult. The structural change in photo-excitation, the deactivation process of Mo-oxide and the effect of Mo atom distribution on the photo-metathesis activity was also investigated. I have already prepared an in-situ X-ray absorption fine structure (XAFS) cell that could be used under irradiation and reaction gas passage. The structural change around Mo atoms under the 1-butene photo-metathesis reaction was observed by using the in-situ XAFS technique.
(1)Mesopore-diameter of MCM-41 was controlled by changing the carbon number of alkyl ammonium (C10-C16). Mo/MCM-41 catalysts were prepared by using MoCl_5 as Mo precursor. Mo was highly dispersed on MCM-41 in these catalysts. XAFS revealed that Mo cluster formed on MCM-41 consists a few atoms. Moreover, the larger the diameter of MCM-41 mesopore became, the smaller the Mo cluster size became.
2)1-Butene photo-metathesis reaction proceeded on Mo/MCM-41 under UV irradiation. The activity of cross-metathesis reaction was promoted as the mesopore-diameter became shorter. In-situ XAFS measurement at PF revealed that the mesopore-diameter of MCM-41 affected the consumption rate of Mo=O site. In other words, photo-metathesis activity depended on the distribution of active site in the pore.
(3)Photo-metathesis activity as well as cross-metathesis activity was promoted on partially pre-reduced Mo/MCM-41 catalysts. It was suggested that reduced-valence species, such as Mo(4+) and Mo(5+), could activate the Mo-O-Mo bridged site toward olefin photo-metathesis reaction.
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