2003 Fiscal Year Final Research Report Summary
Building of the absolute scale for the acidity of zeolites using probe molecules
| Project/Area Number |
14540551
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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 |
物質変換
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| Research Institution | National Science Museum, Tokyo |
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Principal Investigator |
WAKABAYASHI Fumitaka National Science Museum, Tokyo, Department of Science and Engineering, Senior Curator, 理工学研究部, 主任研究官 (30158589)
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| Project Period (FY) |
2002 – 2003
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| Keywords | zeolite / acidic site / acidic hydroxyl / infrared spectroscopy / Lewis acidic site / Bronsted acidic site / probe molecule |
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| Research Abstract |
Acidic sites of zeolites play an important role in the catalytic processes over the zeolites. Hence, the acidic properties of zeolites have been extensively studied using various techniques. However, it is often the case that there are some discrepancies among the results obtained using different techniques or different probe molecules. So, we have carried out a comparative study on the results obtained using pyridine or ammonia that have been traditionally used, dinitrogen that has been recently proposed by the authors, and carbon monoxide that has been widely used in recent years, as infrared spectroscopic probe molecules.
Further, we have investigated the properties of water molecules as an infrared spectroscopic probe molecule of acidic sites. It was shown that water molecules adsorbs preferentially on Lewis acidic sites and then on Brensted acidic sites. Thus water molecules can be used to semi-quantitative measurement of Lewis acidic sites.
The adsorptions of various alkanes with different molecular length on ferierite zeolites, which is the zeolites with small pores, have been studied. This method makes us possible to study the properties of acidic sites near the aperture of the zeolites pores according to their distance from the aperture. Thus it has been found that we can investigate the position of the acidic sites near the pore aperture using chemically similar molecules with different molecular length.
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Research Products
(2 results)
