Comprehensive kinetics of hydrolysis of organotriethoxysilanes by 29Si NMR
The kinetics of several representative hybrid precursors were studied via 29Si NMR: three alkyl precursors, methyltriethoxysilane, ethyltriethoxysilane, and propyltriethoxysilane; as well as two unsaturated radicals, vinyltriethoxysilane and phenyltriethoxysilane. The reaction rate is related to the...
| Autores: | , , , , |
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| Formato: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2019 |
| País: | España |
| Recursos: | Universidad Pública de Navarra |
| Repositorio: | Academica-e. Repositorio Institucional de la Universidad Pública de Navarra |
| OAI Identifier: | oai:academica-e.unavarra.es:2454/47068 |
| Acesso em linha: | https://hdl.handle.net/2454/47068 |
| Access Level: | acceso abierto |
| Palavra-chave: | 29Si NMR Hydrolisis Organotriethoxysilanes |
| Resumo: | The kinetics of several representative hybrid precursors were studied via 29Si NMR: three alkyl precursors, methyltriethoxysilane, ethyltriethoxysilane, and propyltriethoxysilane; as well as two unsaturated radicals, vinyltriethoxysilane and phenyltriethoxysilane. The reaction rate is related to the chemical shift of 29Si in the NMR spectra, which gives information about the electronic density of the Si atoms and the inductive effects of substituents. The concentration of the precursors decreased exponentially with time, and the intermediate products of hydrolysis and the beginning of the condensation reactions showed curves characteristic of sequential reactions, with a similar distribution of the species as a function of the fractional conversion. For all of the precursors, condensation started when the most hydrolyzed species reached a maximum concentration of 0.30 M, when the precursor had run out. A prediction following the developed mathematical model fits the experimental results in line with a common pathway described by eight parameters. |
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