Gas-phase reactions of halogenoalkylsilanes. Part IV. 1-Chloroethyl-diethylchlorosilane and 2-chloroethyltrialkylsilanes

Abstract

The unimolecular elimination ethylene from 2-chloroethyltrimethylsilane k(sec.^–1)= 10^{10·98 ± 0·20} exp –(37,500 ± 800)/RT, and from 2-chloroethyltriethylsilane, k(sec.^–1)= 10^{11·07 ± 0·35} exp –(39,200 ± 1000)/RT, has been studied in the gas phase between 300 and 386°. The results, and earlier ones for similar compounds, are discussed in terms of a four-centre transition state with some charge separation. 1-Chloroethyldiethylchloro-silane has been found to undergo unimolecular dehydrochlorination, k(sec.^–1)= 10^{11·77 ± 0·50} exp –(45,400 ± 1000)/RT, in the gas phase, and the kinetic results are compared with those for the dehydrochlorination of alkyl chlorides. Some general conclusions are drawn about electron distribution in the silicon–chlorine bond.