Naslov
PRECIPITATION AND CHARACTERIZATION OF TWO NOVEL ALUMINIUM HYDROXO PHTHALATES, INDUCED BY SILICIC ACID

Autori
Bilinski, Halka ; Horvath, Laszlo ; Radics, Lajos ; Sjöberg, Staffan ; Ingri, Nils

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
DU'2000 NMR Book of Abstracts The Third International Dubrovnik NMR Course and Conference, June 26-July 1, 2000 / Vikić-Topić, Dražen (ur.). - Dubrovnik : Inter-University Centre Dubrovnik , 2000. 2. / Vikić-Topić, Dražen - Dubrovnik : Interuniverzitetski centar Dubrovnik (IUC), 2000, 2-2

Skup
DU'2000 NMR The Third International Dubrovnik NMR Course and Conference, June 26-July 1, 2000 Dubrovnik, Hrvatska

Mjesto i datum
Dubrovnik, Hrvatska, 26.06.2000. - 01.07.2000

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
precipitation; aluminium hydroxo phthalates; silicic acid; NMR

Sažetak
In the present paper we demonstrate that silicic acid induced precipitation of two different aluminium hydroxo phthalates from the monoclinic Al2(OH)4 phthalate ˇ 4H2O (Sample A). This phase determins the precipitation boundary in H+ - Al3+ - phthalate - Na+ system, studied by Hedlund et al. (1988). The two new solid phases have been characterized from chemical analysis, X-ray analysis of powders, TGA, IR and NMR spectra. At low phthalate to aluminium ratio (N?2), precipitated solid was poorly crystaline and showed variable composition: Al X Si 1.450 - 0.725 X (OH) 3.8 + 0.1X ˇ phthalate ˇ 6 H2O Sample B studied here had x = 1.55. At N?2 precipitated solid showed good crystalinity and constant composition Al OH (phthalate) (Sample C). Both phases B and C contained traces of silicate. From X-ray powder diffractograms it was found that both solids have orthorombic unit cells of different dimensions. 23Na NMR was measured to check if sodium is present in this two solids. A very weak signal appeared as singlet in samples B and C. Samples A, B and C exhibited different broad multicomponent 27Al spectra centered at 0 ppm, characteristic of non-framework, hexacoordinated, octahedral Al atoms. Except for sample A (prepared without Si), samples B and C showed a broad 29Si-MAS NMR spectrum. In sample B the resonance is typical of Al-silicates with high Al content. In sample C it is of none Al-silicates. Calculation of precipitation boundary, using SOLGASWATER program showed that the end member (x = 2) of orthorombic unit cell is the phase which determines precipitation boundary at N?2 and Al OH phtalate at N?2. Formation constants for these two phases have been calculated.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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