text: The process was based on the oxidation of hydrogen chloride: 
  :4 HCl  +  O  →  2 Cl  +  2HO
  The reaction takes place at about 400 to 450 °C in the presence of a variety of catalysts, including copper chloride (CuCl). Three companies developed commercial processes for producing chlorine based on the Deacon reaction:
  *The Kel-Chlor process developed by the M. W. Kellogg Company, which utilizes nitrosylsulfuric acid.
  *The Shell-Chlor process developed by the Shell Oil Company, which utilizes copper catalysts.
  *The MT-Chlor process developed by the Mitsui Toatsu Company, which utilizes chromium-based catalysts.
  The Deacon process is now outdated technology. Most chlorine today is produced by using electrolytic processes. New catalysts based on ruthenium(IV) oxide have been developed by Sumitomo.