Molecular beam mass spectrometry studies of the thermal decomposition of tetraethoxysilane (TEOS)
Molecular beam mass spectrometry and time-of-flight techniques have been used to reveal the gas phase chemistry that occurs during the thermal decomposition of TEOS. Evidence in the authors` laboratory was consistent with the presence of the following species during decomposition at 600{degrees}C: ethylene, ethanol, acetaldehyde, possibly diethoxysilanone, triethoxysilanol, hexaethoxysiloxane. A grayish white powder, which presumably consists of silicon oxides containing residual carbon and hydrogen, was also produced. Under the following reaction conditions: reactor pressure=266 Pa (2 torr), residence time=6 ms, and TEOS partial pressure=26 Pa (0.2 torr), the onset of decomposition occurs at 400{degrees}C. The amount of TEOS decreases at residence times greater than 6 ms with concurrent increase in ethanol and ethylene. Hexaethoxysiloxane also increases at residence times between 6 and 20 ms, but then decreases at longer times probably because it reacts to form larger siloxanes and silicon oxides.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- OSTI ID:
- 110849
- Report Number(s):
- NREL/CP-433-7748; CONF-9410343-; ON: DE95004052; TRN: 95:005145-0024
- Resource Relation:
- Conference: Applications of free-jet, molecular beam, mass spectrometric sampling conference, Estes Park, CO (United States), 11-14 Oct 1994; Other Information: PBD: Mar 1995; Related Information: Is Part Of Applications of free-jet, molecular beam, mass spectrometric sampling: Proceedings; Milne, T. [ed.]; PB: 305 p.
- Country of Publication:
- United States
- Language:
- English
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