1994 Fiscal Year Final Research Report Summary
Relationship between Structural Disorder and Activity of Zeolites
| Project/Area Number |
04453007
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
物理化学一般
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| Research Institution | Toyohashi University of Technology |
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Principal Investigator |
TSUTSUMI Kazuo Toyohashi University of Technology, Faculty of Engineering Professor, 工学部, 教授 (00013178)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUMOTO A Toyohashi University of Technology Research Associate, 工学部, 助手 (90239088)
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| Project Period (FY) |
1992 – 1994
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| Keywords | Zeolite / Structural Disorder / Adsorption / Pore Structure / Zeolitic Activity |
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| Research Abstract |
Peculiar characteristics of zeolites must onginate from their regular crystal structure. However, a number of examples have been reported that zeolitic characteristics are influenced by the presence of several kinds of disorders in their framework. In the present study, correlations between structural disorder and zeolitic acitivity were analyzed.
Zeolites with different values of Si/Al ratio were prepared by treatment with silicon tetrachloride, EDTA and fluorosilicate as well as thermal and acid treatments. Their structure and activivies were analyzed by IR,NMR,calorimetry, fluorination and exchange reaction of framework oxygen. The zeolitic structure retained except on those treated extensively. In case of the dealumination without subsequent Si insertion, so called "hydroxy nest" disorder structure was formed with four hydroxyls which was found to be inactive. Flurination occurred only on the extemal non-acidic hydroxyls which were also formed by dealumination. Fluorinated sites became acidic because of high electronegativity of fluorine of fluorine atoms. Oxygen exchange reaction proceeded on the hydroxyls neibouring to fluorinated sites as well as on essential acidic hydroxyls. Extensive dealumination resulted in the formation of meso-pores without any loss of crystallinity.
A significant role of disorder struature was clarified in the activities and reactivities of zeolites.
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