1993 Fiscal Year Final Research Report Summary
Synthesis of Some Kinds of Metallosilicates by Atom-Planting Method and Their Catalytic Properties
| Project/Area Number |
03453083
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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 |
工業物理化学・複合材料
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
YASHIMA Tatsuaki Tokyo Institute of Technology, Chemistry Department, Professor, 理学部, 教授 (60016409)
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| Co-Investigator(Kenkyū-buntansha) |
KOMATSU Takayuki Tokyo Institute of Technology, Chemistry Department, Assistant Professor, 理学部, 助手 (40186797)
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| Project Period (FY) |
1991 – 1993
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| Keywords | Atom-Planting / MFI Type Zeolite / Mordenite / Alkylation of Aromatics / Shape-Selectivety / Hydroxylation / Oxidative Dehydrogenation / フェリシリケート |
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| Research Abstract |
Some kinds of metallosilicate could be prepared by Atom-Planting method using highly silicious MFI type zeolite and dealuminated mordenite, and metal chlorides. When vapor of metal chloride contacts with highly silicious zeolites at the higher temperatures, the metal cation can occupy the defect sites in zeolite framework.
The acidity of metallosilicates ion-exchanged by proton deferred to the kind of trivalent metal cation inserted into the framework. The order of acid strength of some metallosilicates was measured as follows ;
As-> Ga-> Fe-> In-> Sb-> As-
When these metallosilicates were used as a catalyst for the alkylation of monoalkylbenzene, the fraction of para isomer in dialkylbenzene produced reached 80-100%. It can be concluded from the results obtained by using metallosilicate catalysts with same pore window size but different acid strength that para isomer is shape-selectively produced through the transition state restriction.
The transition-metal cation inserted into the zeolite framework was a tetrahedral state and was not easily reduced nor oxidized. Therefore, it is expected that the catalytic properties of transition-metal cations in zeolite framework would be different from those in oxides and coplex compounds. Iron cation with tri-valent state in zeolite framework showed the high activity for the oxidative dehydrogenation and the low activity for the complete oxidation of lower paraffins, while iron oxide showed the high activity for the complete oxidation of lower paraffins. On the other hand, titanosilicate with mordenite type structure could be prepared by Atom-Planting method, and showed high catalytic activity for the liquid phase hydroxylation of benzene ring with hydrogen peroxide.
From these results it is concluded that Atom-Planting is a good method for the preparation of metallosilicates and these metallosilicates will show the unique catalytic properties for some reactions.
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