Etude par Spectrométrie Raman Rapide de la Cinétique d'Addition de l'Acide Chlorhydrique à des Doubles Liaisons Conjuguées: Cas du cis ‐2, trans ‐4‐Hexadiène

The kinetic study of thermal dehydrochlorination of 4‐chloro‐2‐hexene (model of an allylic unstable structure occurring in polyvinyl chloride during its degradation) has shown that the reaction is reversible and has an ionic mechanism. The activation energies for the addition of hydrogen chloride to conjugated double bonds of cis ‐2‐, trans ‐4‐hexadiene in ethanol or dichloroethane have been determined by rapid Raman spectroscopy as 71.1 ± 10.4 kJ mol −1 and 36.8 ± 5.0 kJ mol −1 respectively from plots of the intensity ratio I ν(CC) / I   δ(CH   2 )against time at various temperatures.