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Liquid-phase reactions of CCl/sub 3/ radicals with trimethylsilane and triethylsilane. [Gamma rays]

Journal Article · · J. Phys. Chem.; (United States)
DOI:https://doi.org/10.1021/j100457a010· OSTI ID:6873524

The ..gamma..-radiation-induced chain reactions in liquid solution of silane (R'/sub 3/SiH) in CCl/sub 4/-c-C/sub 6/H/sub 12/(RH) mixtures were investigated over the temperature range 303-423 K for R' = Me and 335-423 K for R' = Et. In both systems the main products are R'/sub 3/SiCl, CHCl/sub 3/, and RCl. By kinetic analyses of product distribution, the rate constants of hydrogen abstraction from the two silanes by CCl/sub 3/ radicals were competitively determined vs. hydrogen abstraction from cyclohexane. The relative rate constants combined with the known Arrhenius parameters of the reference systems gave the following Arrhenius parameters for the reaction CCl/sub 3/ + R'/sub 3/SiH ..-->.. CHCl/sub 3/ + R'/sub 3/Si: log A/sub 4/ (L mol/sup -1/s/sup -1/) = 8.49 and E/sub 4/ = 8.70 kcal mol/sup -1/ when R' = Me, and log A/sub 4/ = 8.62 and E/sub 4/ = 8.06 when R' = Et. These results indicate that alkyl-substituted silanes are considerably more reactive than Cl/sub 3/SiH in the H-atom transfer reactions with CCl/sub 3/ radicals. This observation is rationalized in terms of the polar effects of the alkyl substituents.

Research Organization:
Soreq Nuclear Research Center, Yavne, Israel
OSTI ID:
6873524
Journal Information:
J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Journal Issue: 20 Vol. 84:20; ISSN JPCHA
Country of Publication:
United States
Language:
English