Free-radical chain dechlorination of chloroethanes in liquid triethylsilane

✍ Scribed by R. Aloni; L. A. Rajbenbach; A. Horowitz

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: English
• Weight: 714 KB
• Volume: 13
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550130104

✦ Synopsis

The kinetics and mechanism of the free-radical chain dechlorination of CZCIS, C~CISH, and sym-CzCl4Hz in EtgSiH were investigated over a wide temperature range. The propagation step of the dechlorination of chloroethanes (C&I,H+r) proceeds by the following reactions:

(2)

C1+ EtsSiH -HCI + EtaSi Analysis of the temperature dependence of product formation gave the Arrhenius expressions for k4/k3 which in turn were utilized for the estimation of the absolute Arrhenius parameters for hydrogen abstraction from EtZSiH. Our results show that the values of Eabs are lower in EtgSiH than in c-CsHlz by about 2-3 kcal/mol, while the A factors are almost equal. In competitive studies k z was determined versus Br abstraction from n-CsH11Br. The relative Arrhenius parameters determined by this method show that variations in both A factors and activation energies are responsible for the reactivity trends observed in the C1 transfer reactions of EtgSi radicals.