Multinuclear NMR study of aluminosilicate sol-gel synthesis using the prehydrolysis method

Pozarnsky, G. A.; McCormick, Alon V.

doi:10.1016/0022-3093(95)00240-5

Cited by 48 publications

(15 citation statements)

References 23 publications

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“…The synthesis protocol used was a variation from the method described in Pozarnsky and McCormick [27], where the silica precursor was allowed to ''prehydrolyze'' in water at pH 3 for a period of 10 min at room temperature. After this prehydolysis step, the aluminum precursor, previously homogenously dissolved in 10 ml of sec-butyl alcohol, was added and stirred until complete homogenization.…”

Section: Nanoaluminosilicatesmentioning

confidence: 99%

Using alkali-activated natural aluminosilicate minerals to produce compressed masonry construction materials

Muñoz

Easton

Dahmen

2015

Construction and Building Materials

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Section: Nanoaluminosilicatesmentioning

confidence: 99%

Using alkali-activated natural aluminosilicate minerals to produce compressed masonry construction materials

Muñoz

Easton

Dahmen

2015

Construction and Building Materials

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“…18 The chemical shift of the tetrahedral aluminum peak (62-63 ppm) corresponds to aluminum that has been protected by 2-3 silicate ligands. 2,[18][19][20][21] The new and interesting feature with excess Al, though, is the penta-coordinated aluminum peak at 38 ppm; it is identical to one of the peaks from the precursor secbutoxide complex. 2 There may also be tetrahedral Al still in the alkoxide complex in the broad tetrahedral region.…”

Section: B After Aluminum Addition: Stage Bmentioning

confidence: 99%

“…1], the prehydrolysis of the silicon alkoxide can allow the formation of transparent gels. 2 Provided the aluminum to silicon ratio is kept low enough so that all of the aluminum can be protected by silanols, a homogeneous aluminosilicate gel can be obtained in several tetra-alkoxysilane/alcohol/aluminum sec-butoxide [TROS͞ROH͞Al(OBu s ) 3 , where R alkyl group] systems. 2 Provided the aluminum to silicon ratio is kept low enough so that all of the aluminum can be protected by silanols, a homogeneous aluminosilicate gel can be obtained in several tetra-alkoxysilane/alcohol/aluminum sec-butoxide [TROS͞ROH͞Al(OBu s ) 3 , where R alkyl group] systems.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] We have recently shown that one reason this protocol works is that the silanols prepared in the prehydrolysis step react with the aluminum precursor, protecting aluminum sites from direct hydrolysis by water (which is added only after the "protecting" reaction has been accomplished). [1][2][3] At high ratios of aluminum to silicon precursors (Al͞Si . [1][2][3] At high ratios of aluminum to silicon precursors (Al͞Si .…”

Section: Introductionmentioning

confidence: 99%

“…2 Provided the aluminum to silicon ratio is kept low enough so that all of the aluminum can be protected by silanols, a homogeneous aluminosilicate gel can be obtained in several tetra-alkoxysilane/alcohol/aluminum sec-butoxide [TROS͞ROH͞Al(OBu s ) 3 , where R alkyl group] systems. 2 This usually allows the aluminum precursor to be directly attacked by water, and hence leads to alumina precipitation. 0.25), we found that some excess aluminum sites remain unprotected by silicate ligands.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The role of transesterification in the multistep “prehydrolysis” sol/gel synthesis of aluminum-rich aluminosilicate gels

Pozarnsky

McCormick

1996

J. Mater. Res.

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Using a prehydrolysis technique, transparent gels with very high aluminum content can be achieved with the use of isopropanol. Here 13 C, 27 Al, 29 Si and 17 O NMR at various stages of preparation show that when the aluminum added exceeds the number that silanols can fully protect, the excess aluminum alkoxide groups readily undergo transesterification with isopropanol. The aluminum isopropoxide (Al-OPr i ) groups thus formed are shown to be sufficiently stable that attack by water is impeded, thus allowing the remaining silicon alkoxide groups to hydrolyze and condense to form a homogeneous gel.922

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Nuclear Magnetic Resonance of Geological Materials and Glasses

Moran

Howe

2000

Encyclopedia of Analytical Chemistry

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This article concerns the application of nuclear magnetic resonance (NMR) spectroscopic techniques to the analysis of geological materials and glasses. It includes inorganic minerals and glasses, but does not cover soils and clay minerals to any extent. The first part presents an overview of solid‐state NMR experiments applicable to inorganic solids. The range of nuclei accessible by NMR and the particular requirements for obtaining good spectra of more difficult nuclei, including quadrupolar nuclei, are discussed. The experimental conditions under which solid‐state NMR can provide quantitative analytical measurements are also considered. NMR spectroscopy provides element‐specific speciation and structural information including coordination environment and bond distances. It is particularly valuable for the analysis of amorphous and partially crystalline materials not amenable to structure determination by X‐ray diffraction. NMR can detect and quantify materials containing multiple phases and can be used for in situ monitoring of phase transitions. It provides qualitative and quantitative speciation information for framework nuclei in glasses and is also capable of characterizing the dynamic behavior of mobile ions and solvent through relaxation, diffusion and chemical exchange experiments. Thus it has become an important technique for the study of hydrous minerals and gels and for ion‐conducting glasses. The sensitivity of NMR varies considerably, depending on the nucleus observed, its abundance and its chemical environment. NMR sensitivities and detection limits cannot compete with elemental analytical techniques such as X‐ray fluorescence. In addition, quantitation in solids requires careful control of experimental parameters and careful calibration to avoid artifacts. However, the selectivity of NMR as an analytical technique is unsurpassed and the development of specialist pulse sequences to measure specific local interactions in solids makes it particularly well suited to the analysis of geological materials and glasses. NMR imaging enables structural information to be resolved in three dimensions, although resolution in solid‐state imaging is limited to tens of micrometers at best owing to the broader line widths and lower signal‐to‐noise ratios compared with liquids. However, capabilities in this field are being extended all the time and the application of NMR imaging techniques in materials analysis is expanding steadily. An alternative to conventional imaging is NMR force microscopy, which shows potential for surface mapping at higher resolutions. The applications section is organized on the basis of the materials being analyzed. Within each section, NMR techniques are classified according to the observed nuclei. The emphasis is on more recent applications and on developments leading to enhanced resolution and sensitivity. Silicates and aluminosilicates represent the largest class of applications, followed by phosphate, borate and other oxide glasses. Sol–gel materials and the reactions leading to gel formation are also discussed, as are hydrous materials more generally. The other important areas of application reviewed are minerals, ceramics, high‐temperature melts and ion‐conducting glasses. Finally, the applications of NMR imaging in this field, although sparse at present, are potentially very great. This is illustrated by two major areas of application to date, namely the imaging of bone minerals and cement and concrete.

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Multinuclear NMR study of aluminosilicate sol-gel synthesis using the prehydrolysis method

Cited by 48 publications

References 23 publications

Using alkali-activated natural aluminosilicate minerals to produce compressed masonry construction materials

Using alkali-activated natural aluminosilicate minerals to produce compressed masonry construction materials

The role of transesterification in the multistep “prehydrolysis” sol/gel synthesis of aluminum-rich aluminosilicate gels

Nuclear Magnetic Resonance of Geological Materials and Glasses

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