The Deacon process, invented by
Henry Deacon, is a process used during the
manufacture of
alkalis (the initial end product was
sodium carbonate) by the
Leblanc process.
Hydrogen chloride
The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride ga ...
gas was converted to
chlorine
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...
gas, which was then used to manufacture a commercially valuable
bleaching powder
Bleach is the generic name for any chemical product that is used industrially or domestically to remove color (whitening) from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically, to ...
, and at the same time the emission of waste
hydrochloric acid
Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid
Acid strength is the tendency of an acid, symbol ...
was curtailed. To some extent this technically sophisticated process superseded the earlier
manganese dioxide 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 (CuCl2). Three companies developed commercial processes for producing chlorine
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...
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, which utilizes nitrosylsulfuric acid
Nitrosylsulfuric acid is the chemical compound with the formula . It is a colourless solid that is used industrially in the production of caprolactam, and was formerly part of the lead chamber process for producing sulfuric acid. The compound is ...
.
*The Shell-Chlor process developed by the Shell Oil Company
Shell USA, Inc. (formerly Shell Oil Company, Inc.) is the United States-based wholly owned subsidiary of Shell plc, a UK-based transnational corporation " oil major" which is amongst the largest oil companies in the world. Approximately 18,0 ...
, 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 process
An electrolytic process is the use of electrolysis industrially to refine metals or compounds at a high purity and low cost. Some examples are the Hall-Héroult process used for aluminium, or the production of hydrogen from water. Electrolysis i ...
es. New catalysts based on ruthenium(IV) oxide
Ruthenium(IV) oxide is the inorganic compound with the formula Ru O2. This black solid is the most common oxide of ruthenium. It is widely used as an electrocatalyst for producing chlorine, chlorine oxides, and O2. Like many dioxides, RuO2 adop ...
have been developed by Sumitomo.[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. In this process, hydrogen chloride
The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride ga ...
is oxidized by oxygen over a copper chloride catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
, resulting in the production of chlorine
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...
. This was widely used in the paper and textile industries as a bleaching agent, and as a result sodium carbonate was no longer the primary product of these plants, and henceforth sold at a loss.
See also
* Chlorine production Chlorine gas can be produced by extracting from natural materials, including the electrolysis of a sodium chloride solution (brine) and other ways.
Gas extraction
Chlorine can be manufactured by the electrolysis of a sodium chloride solution (bri ...
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