Chlorine is extracted from sea salt via electrolysis, and ethylene is derived from hydrocarbon raw materials. These are reacted to produce ethylene dichloride (1,2-dichloroethane) according to the reaction:

C2H4 + Cl2 = C2H4Cl2

ethylene + chlorine = ethylene dichloride

Step 2 Producing Vinyl Chloride Monomer (VCM)

The ethylene dichloride is then decomposed by heating in a high temperature furnace, according to the reaction:

C2H4Cl2 = C2H3Cl + HCl

ethylene dichloride = vinyl chloride monomer + hydrogen chloride

The hydrogen chloride is reacted with more ethylene in the presence of oxygen (a reaction known as oxychlorination) to produce further ethylene dichloride. The ethylene dichloride so produced is decomposed according to the above equation, and the hydrogen chloride again returned for oxychlorination.

2HCl + C2H4 + ½ O2 = C2H4Cl2 + H2O = C2H3Cl + HCl2 + H2O

The overall reaction can be shown by adding together the above equations to give:

2C2H4 + Cl2 + ½ O2 = 2C2H3Cl + H2O

ethylene + chlorine + oxygen = VCM + water

Click on the diagram below for an outline of the process.

Step 3 Manufacturing Polyvinyl Chloride (PVC)

PVC is made by a process called addition polymerization. This reaction opens the double bonds in the vinyl chloride monomer (VCM) allowing neighboring molecules to join together creating long chain molecules.

nC2H3Cl = (C2H3Cl)n

Vinyl chloride = polyvinyl chloride