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 + SiHCl₃ + RH + SiCl₃

R	Temp (°K)	E(kcal/mole)	Log A(mole?1 cc sec?1)	Log k(400°K) (mole?1 cc sec?1)
CF3	323–461	5.98 ± 0.06	11.77 ± 0.03	8.50
CH3	333–443	4.30 ± 0.08	10.83 ± 0.04	4.48
C2H5	314–413	5.32 ± 0.07	11.54 ± 0.04	8.63

The trend in activation energies E < E < E is interpreted as indicating a polar effect in the reaction of CF₃ with SiHCl₃ 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 CH₃ abstracting an H atom from SiHCl₃ have been amended.