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The Deacon process, invented by Henry Deacon, is a process used during the
manufacture Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of secondary sector of the economy. The term may refer to a rang ...
of
alkali In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a ...
s (the initial end product was
sodium carbonate Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...
) by the
Leblanc process The Leblanc process (pronounced leh-blaank) was an early industrial process for making ''soda ash'' (sodium carbonate) used throughout the 19th century, named after its inventor, Nicolas Leblanc. It involved two stages: making sodium sulfate from ...
. 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 To some extent this technically sophisticated process superseded the earlier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 Manganese dioxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-cell ...
process.


Process

The process was based on the oxidation of hydrogen chloride: :4 HCl + O2 → 2 Cl2 + 2H2O The reaction takes place at about 400 to 450 °C in the presence of a variety of catalysts, including
copper chloride Copper chloride may refer to: * Copper(I) chloride (cuprous chloride), CuCl, mineral name nantokite * Copper(II) chloride Copper(II) chloride is the chemical compound with the chemical formula CuCl2. The anhydrous form is yellowish brown but slo ...
(CuCl2). Three companies developed commercial processes for producing chlorine based on the Deacon reaction:Peter Schmittinger et al. "Chlorine," Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH Verlag GmbH & Co, 2006, *The Kel-Chlor process developed by the
M. W. Kellogg Company KBR, Inc. (formerly Kellogg Brown & Root) is a U.S. based company operating in fields of science, technology and engineering. KBR works in various markets including aerospace, defense, industrial and intelligence. After Halliburton acquired Dress ...
, 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 The is one of the largest Japanese ''keiretsu'', or business groups, founded by Masatomo Sumitomo (1585-1652) around 1615 during the early Edo period. History The Sumitomo Group traces its roots to a bookshop in Kyoto founded circa 1615 by Masa ...
.K. Seki, Catal. Surv. Asia 14, 168 (2010) .


Leblanc-Deacon process

The Leblanc-Deacon process is a modification of the Leblanc process. The Leblanc process was notoriously environmentally unfriendly, and resulted in some of the first Air and Water pollution acts. In 1874, Henry Deacon had derived a process to reduce HCl emissions as mandated by the
Alkali Act The Alkali Act 1863 (26 & 27 Vict c 124) was an Act of the Parliament of the United Kingdom. Under the Alkali Act 1863, an alkali inspector and four subinspectors were appointed to curb discharge into the air of muriatic acid gas (gaseous hyd ...
. In this process, hydrogen chloride is oxidized by oxygen over a
copper chloride Copper chloride may refer to: * Copper(I) chloride (cuprous chloride), CuCl, mineral name nantokite * Copper(II) chloride Copper(II) chloride is the chemical compound with the chemical formula CuCl2. The anhydrous form is yellowish brown but slo ...
catalyst, resulting in the production of chlorine. This was widely used in the paper and textile industries as a bleaching agent, and as a result
sodium carbonate Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...
was no longer the primary product of these plants, and henceforth sold at a loss.


See also

* Chlorine production


References


External links

* http://www.che.lsu.edu/COURSES/4205/2000/Lim/paper.htm * http://www.electrochem.org/dl/interface/fal/fal98/IF8-98-Pages32-36.pdf * Deacon chemistry revisited: new catalysts for chlorine recycling. ETH (2013). {{doi, 10.3929/ethz-a-010055281; https://dx.doi.org/10.3929/ethz-a-010055281 Chemical processes Inorganic reactions Chlorine