Hydrogen abstraction reactions from organosilicon compounds. The reactions of methyl, trifluoromethyl, and ethyl radicals with trichlorosilane

Arrhenius parameters have been determined for the hydrogen‐abstraction reactions:R + SiHCl 3 + RH + SiCl 3TextR Temp (°K) E (kcal/mole) Log A (mole −1 cc sec −1 ) Log k (400°K) (mole −1 cc sec −1 )CF 3 323–461 5.98 ± 0.06 11.77 ± 0.03 8.50 CH 3 333–443 4.30 ± 0.08 10.83 ± 0.04 4.48 C 2 H 5 314–413 5.32 ± 0.07 11.54 ± 0.04 8.63The trend in activation energies E   CH   3< E   C   2 H   5< E   CF   3is interpreted as indicating a polar effect in the reaction of CF 3 with SiHCl 3 and the similar reactivities of all three radicals appear to be due to the high exothermicity of the reactions. The A Factors for the reactions are normal for hydrogen abstraction reactions of free radicals. The previous results of Kerr, Slater, and Young for CH 3 abstracting an H atom from SiHCl 3 have been amended.