The second process, the EDC/VCM Process, produces vinyl chloride monomer (VCM) as the main product. Commercial EDC/VCM Process consists of two type of processes, the Direct Chlorination process and the Oxy-Chlorination process. In Direct Chlorination process, chlorine generated in the Chlor-Alkali process is reacted with ethylene to produce ethylene dichloride (EDC), an industrial solvent used mainly to produce VCM.

In the Oxy-Chlorination process, ethylene, hydrochloric acid and oxygen are reacted to give ethylene dichloride.

Ethylene dichloride is then subjected to “cracking” process to give VCM and hydrochloric acid (HCl) as by-product. Some of the produced hydrochloric acid is utilized in the Oxy-Chlorination process to produce VCM, while the rest is delivered to customers.

In the Direct Chlorination process, ethylene is first chlorinated to produce ethylene dichloride (CH₂Cl-CH₂Cl).

            CH₂=CH₂  +  Cl₂  → CH₂Cl-CH₂Cl

Ethylene dichloride is subsequently subjected to thermal cracking process (pyrolyzed) to produce vinyl chloride (CH₂=CHCl)  and hydrogen chloride (HCl).

            CH₂Cl-CH₂Cl  → CH₂=CHCl  + HCl

In the Oxy-Chlorination process, ethylene, hydrochloric acid (HCl) from the Second Reaction and oxygen (O₂) are reacted to form ethylene dichloride (CH₂Cl-CH₂Cl).

            CH₂=CH₂  +  Cl₂ + ½ O₂ → CH₂Cl-CH₂Cl + H₂O

Adding those reactions above gives the overall reaction for balanced process:

            2 CH₂=CH₂  +  Cl₂ + ½ O₂ → 2 CH₂=CHCl + H₂O