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Synthesis of mesoporous supported materials on base of H3PMo12O40 and silica

Volodymyr Sydorchuk ,  Valeriy Zazhigalov ,  Svitlana Khalameida 

Institute of Sorption and Problems of Endoecology NAS of Ukraine, 13 Gen Naumova Str., Kyiv 03164, Ukraine


Solid tugstophosphoric acid (TPA) is very strong Brensted acid. It is applied both in acid catalysis and as solid electrolytes. Often it is necessary to deposit it on suitable support with developed porous structure. We have used homogeneously-mesoporous silica which was prepared on basis its pyrogenic form as support. TPA is fixed chemically on silica surface. For achievement this silica was undergone preactivation by interaction with -aminopropyltriethoxisilan: extent of grafting 0,34 (support 1) and 0,68 mmol/g (2). Reaction TPA with modified silica was carried out in aqueous or acetone solutions either at 20C or under high pressure and temperature in autoclave. Some results are presented in the table. TPA is connected chemically with silica surface: absorption bands 805, 895 and 983 cm-1 indicate at presence of Keggin-structure on surface, DTA-TGA at its high thermostability. The surface organic rests are also sufficiently stable. It is interesting that both hydrophobic and hydrophilic groups are on surface. Thus hybrid materials are obtained. General acidity of prepared samples which was determined by adsorption of pyridine decreases at deposition of TPA on surface. Preliminary chemical activation of support permits to obtain samples with higher concentration of acid groups than at impregnation of initial silica. Geometrical modification of support also occurs: surface area, volume and pore size change in wide limits. Support Conditions of treatment S,m2/g V,ml/g d,nm General acidity, mol/m2 Bulk TPA 5 0,780 Initial silica 303 1,10 14,5 0,009 Initial silica Impregnation by TPA 192 0,96 20,0 0,035 Support 1 Acetone solution, 20C 118 0,51 17,5 0,023 150C 96 0,41 17,0 0,034 Support 2 Acetone solution, 20C 80 0,39 19,5 0,039 150C 49 0,40 32,5 0,065 Water solution, 200C 89 0,39 17,5 0,052


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Presentation: Poster at E-MRS Fall Meeting 2007, Symposium A, by Volodymyr Sydorchuk
See On-line Journal of E-MRS Fall Meeting 2007

Submitted: 2007-05-13 13:53
Revised:   2009-06-07 00:44