Kinetics of dichlorosilylene trapping by methane and mechanism and kinetics of the methyldichlorosilane decomposition

✍ Scribed by M. A. Ring; H. E. O'Neal; K. L. Walker

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 165 KB
• Volume: 30
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/(sici)1097-4601(1998)30:1<89::aid-kin10>3.0.co;2-g

✦ Synopsis

Data relative to methane trapping of SiCl 2 and a rate constant for the SiCl 2 into C9 H bond insertion process of 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 at 905 K

Ϫ3 Ϫ1

k ϭ 1.5 Ϯ 0.2 ϫ 10 s 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 91 : Free CH ϩ SiCl .

4 2 radicals and Si9 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.