Dehydrochlorination of Poly (vinyl chloride) in the Presence of Iron (III) Chloride Catalyst

Abstract

Dehydrochlorination of poly (vinyl chloride) (PVC) in the presence of FeCl₃ has been studied. FeCl₃ showed a pronounced catalytic effect on the rate of the dehydrochlorination of PVC. Its catalytic activity, however, decreased with increasing reaction time. This catalyst deactivation was attributable to the reduction of FeCl₃ by the polyenes formed in PVC, because the resulting FeCl₂ exhibited a very low catalytic activity for the dehydrochlorination reaction. Two kinds of reaction mechanisms were suggested to account for the reduction of the FeCl₃ catalyst. One was the reaction occurring among FeCl₃, polyenes and water molecule with the evolution of HCl, which was accelerated in the presence of water vapor. The other was electron transfer from polyenes to FeCl₃ without participation of water molecule. These reduction reactions seem to proceed competitively.