EDC/VCM PROCESS

Ethylene is currently the predominant raw material for vinyl chloride production. The commercially practiced vinyl chloride production involves a balanced combination of Direct Chlorination (DC) and Oxy-Chlorination (OC) processes.

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

            CH₂=CH₂  +  Cl₂  → CH₂Cl-CH₂Cl                                        (1)

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                                      (2)

In the Oxy-Chlorination process, ethylene, hydrochloric acid (HCl) from Reaction (2) and oxygen (O₂) are reacted to form ethylene dichloride (CH₂Cl-CH₂Cl).

            CH₂=CH₂  +  Cl₂ + ½ O₂ → CH₂Cl-CH₂Cl + H₂O                  (3)

Adding Reactions (1), (2) and (3) gives the overall reaction for balanced process:

            2 CH₂=CH₂  +  Cl₂ + ½ O₂ → 2 CH₂=CHCl + H₂O                (4)