the present invention relates to a process for dehydrochlorinating polyvinylchloride polymers to remove about 30 wt % chlorine therefrom by heating the starting materials pvc and deoxygenated liquid water , preferably neutral liquid water at temperatures from about 200 ° c . up to the critical temperature of water at autogenous pressure to maintain the water as a liquid phase . the process has utility in recycling by enabling pvc to be dechlorinated specifically by a means that does not release chlorine gas .