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Kinetics of dichlorosilylene trapping by methane and mechanism and kinetics of the methyldichlorosilane decomposition
Author(s) -
Ring M. A.,
O'Neal H. E.,
Walker K. L.
Publication year - 1998
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/(sici)1097-4601(1998)30:1<89::aid-kin10>3.0.co;2-g
Subject(s) - chemistry , kinetics , decomposition , thermochemistry , reaction rate constant , methane , reaction mechanism , thermal decomposition , chemical kinetics , silylene , trichlorosilane , organic chemistry , catalysis , silicon , physics , quantum mechanics
Data relative to methane trapping of SiCl 2 and a rate constant for the SiCl 2 into C(SINGLEBOND)H bond insertion process of k −1 =13.4 M −1 s −1 at 921 K are reported. Results on the decomposition of the trapping product, methyldichlorosilane, are also reported. This decomposition follows first‐order kinetics with a rate constant of k =1.5±0.2×10 −3 s −1 at 905 K and produces methane, trichlorosilane, methyltrichlorosilane, and tetrachlorosilane. It is argued that the decomposition involves silylene intermediates, is nonchain, and is initiated primarily by the molecular methane elimination process MeSiHCl 2 (SINGLEBOND)1→ CH 4 +SiCl 2 . Free radicals and Si(SINGLEBOND)C bond fission may also contribute to the decomposition but are not dominant. The kinetics of MeSiHCl 2 decomposition are shown to be consistent with the kinetics of the reverse SiCl 2 /CH 4 trapping reaction and with the overall reaction thermochemistry. Reaction modeling gives product yields, reactant conversions, and rates in reasonable agreement with the data. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 89–97, 1998.