| Abstract: | Films of polyvinylidene chloride (PVDC) were heterogeneously dehydrochlorinated by reacting them with KF-crown and KOH-crown complexes dissolved in benzene. Solutions were in contact with an excess of unhydrous salts. This three-phase reaction was very fast at 80°C and the removal of one chlorine atom per monomer unit was completed within 1 h. Further dehydrochlorination leads to triple-bond formation and to aromatization of the system due to the intramolecular 1,6 elimination. The former reaction is dominant when KOH-crown is used as the dehydrochlorinating agent and the latter is dominant in KF-crown/CaO systems. The apparent energy of activation of the initial dehydrochlorination process is estimated to be 6.7 kcal./mol. |
