What is "deacon process"

The Deacon process is a process used during the manufacture of alkalis (the initial end product was sodium carbonate) by the Leblanc process. Hydrogen chloride gas was converted to chlorine gas, which was then used to manufacture a commercially valuable bleaching powder, and at the same time the emission of waste hydrochloric acid was curtailed. To some extent this technically sophisticated process superseded the earlier manganese dioxide process.

Invented by Henry Deacon in 1874. The process was based on the oxidation of hydrogen chloride:

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The Deacon process is now outdated technology.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.