| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1986: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1985: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
Preparation of new zeolite-like compounds containing niobium or tantalum was attempted under the hydrothermal conditions in the presence of quaternary ammonium ions. The starting materials were polyniobate, polytantalate or amorphous oxide and the preparative temperature ranged from 90 to 200゜C.
1. Preparation of compounds of which structures are composed of <NbO_6> or <TaO_6> octahedra. In the system of <A_2O> , <Q_2O> - <Nb_2O_5> , <Ta_2O_5> - <H_2O> (A; alkali metal, Q; quaternary ammonium), <NaNbO_3> with ilmenite type structure, <Li_(3-x)H_xTaO_4> with NaCl type structure and <A_(1-x)H_xTaO_3> ・n <H_2O> with pyrochlore type structure were prepared, containing no quaternary ammonium. These compounds do not have micro pores comparable with those in zeolites.
2. Preparation of micro porous materials from layered compound. Large hydroxo complex ions were attempted to be inserted into the interlayer spaces of <K_4Nb_6O_(17)> ・n <H_2O> by ion exchange. The complex ions of Ni and Al were t
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aken up into the interlayer spaces, giving large basal spacings. But thermal stabilities of these materials were less than similar materials obtained from clay minerals.
3. Preparation of compounds with framework composed of several kinds of polyhedra. In the system of <Na_2O> - <Q_2O> - <Nb_2O_5> - <P_2O_5> - <H_2O> , several new compounds related to layered compound, <NbOPO_4> ・n <H_2O> , were obtained, when <Nb_2O_5> / <P_2O_5> was <1/18.Those are considered to have structure in which the layers of <NbOPO_4> are linked with strong hydrogen bond or <PO_4> tetrahedra. A compound with the latter three dimensional structure contains quaternary ammonium ions exchangeable with other cations and zeolitic water in the structure. Therefore this compound is considered to be a new zeolite-like compound with micro pore. Further investigation on this compound is desirable.
Attempts by using <Al_2O_3> , <Bi_2O_3> , <SiO_2> , <ZrO_2> and <Sb_2O_5> resulted in the formation of amorphous materials or compounds with bad cryistallinity. Less
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