Solid-state NMR studies of the reactions of silica surfaces with polyfunctional chloromethylsilanes and ethoxymethylsilanes
The silylation of silica (Si) surfaces by dimethyldichlorosilane, methyltrichlorosilane, dimethyldiethoxysilane, and methyltriethoxysilane has been studied by solid-state /sup 29/Si and /sup 13/C NMR, by use of cross polarization (CP) and magic-angle spinning (MAS). An earlier formalism for the quantitative analysis of the NRM data has been extended for use with polyfunctional silyating agents and applied in detail to dimethyldichlorosilane reactions. Silylation with ethoxysilane reagents is less amenable to quantitative interpretation but appears to parallel closely the behavior of analogous chlorosilane reagents. With ethoxysilane reagents /sup 13/C NMR is found to be quite useful, especially for determining the fate of ethoxy groups. In all of the cases studied, the products are characterized primarily by single silane-to-surface attachments of each silane silicon atom. The presence of absorbed water is found to play an important role in the course and rate of the silylation reactions, especially those employing ethoxysilane reagents. The NMR data are used to address the question of horizontal and vertical polymerization within the silane phase on the silica surface.
- Research Organization:
- Colorado State Univ., Fort Collins
- DOE Contract Number:
- AS20-81LC10652
- OSTI ID:
- 5614776
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 105:12
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
SILANES
CHEMICAL REACTIONS
STRUCTURAL CHEMICAL ANALYSIS
SILICA
CHEMICAL SHIFT
EXPERIMENTAL DATA
HYDRATES
NMR SPECTRA
ORGANIC CHLORINE COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC SOLVENTS
SILICA GEL
TIME DEPENDENCE
TOLUENE
ADSORBENTS
AROMATICS
CHALCOGENIDES
DATA
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
INFORMATION
MINERALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
SILICON COMPOUNDS
SILICON OXIDES
SOLVENTS
SPECTRA
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)
400201 - Chemical & Physicochemical Properties