Incorporation of aluminum into silicate anions in aqueous and methanolic solutions of TMA silicates

Journal Article · Thu Oct 03 04:00:00 EDT 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100173a054· OSTI ID:7265879

Mortlock, R F; Bell, A T; Radke, C J ^[1]

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1. Lawrence Berkeley Lab., CA (United States)

{sup 29}Si and {sup 27}Al NMR spectroscopies were used to characterize dilute, highly alkaline, aqueous and methanolic solutions of tetramethylammonium (TMA) aluminosilicates. The solutions contained 2 mol% SiO{sub 2}, a silicate ratio (R=(SiO{sub 2})/(M{sub 2}O), M{sup +} = TMA{sup +}) of 2, Si/Al molar ratios between {infinity} and 2, and between 0 and 20 mol% methanol (MeOH). TMA aluminosilicate solutions are characterized by a high concentration of double four membered ring (D4R) anions. {sup 29}Si NMR peaks were observed for Si atoms in the dimer, linear trimer, cyclic trimer, branched cyclic trimer, and D4R anions which have one incorporated Al atom. {sup 29}Si NMR peak assignments were based on similar assignments in tetrapropylammonium (TPA) aluminosilicate solutions and confirmed by using the correlation between the partial charge of Si atoms and the {sup 29}Si NMR chemical shift. Comparison between the distribution of silicate and aluminosilicate oligomers in TMA and TPA aluminosilicate solutions indicates that the distribution of Si atoms among anions is very different, but the level of Al incorporation into silicate species is remarkably similar. As a result, the incorporation of Al into silicate anions depends strongly on the solution composition and pH and depends only weakly on the nature of the alkylammonium base. Due to a hydrophobic effects, the addition of methanol to TMA aluminosilicate solutions increases the concentration of D4R and D4R(1Al) anions.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 7265879
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:20; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ACID NEUTRALIZING CAPACITY
ALCOHOLS
ALUMINIUM
ALUMINIUM 27
ALUMINIUM COMPOUNDS
ALUMINIUM ISOTOPES
ALUMINIUM SILICATES
AMINES
ANIONS
AQUEOUS SOLUTIONS
CHARGED PARTICLES
CHEMISTRY
DATA
DISPERSIONS
ELEMENTS
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HYDROXY COMPOUNDS
INFORMATION
IONS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
METALS
METHANOL
MIXTURES
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
RESONANCE
SILICATES
SILICON 29
SILICON COMPOUNDS
SILICON ISOTOPES
SOLUTIONS
STABLE ISOTOPES
SYNTHESIS
WATER CHEMISTRY