Deacon process
Encyclopedia
The Deacon process was a secondary process used during the manufacture of alkali
s (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 To some extent this technically sophisticated process superseded the earlier manganese dioxide process.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 this reaction:
The reaction takes place at about 400 to 450 °C in the presence of a copper chloride
(CuCl2) catalyst. Three companies developed commercial processes for producing chlorine
based on the Deacon reaction:
The Deacon process is now outdated technology. Most chlorine today is produced by using electrolytic process
es.
However, recent developments with new catalysts based on Ruthenium(IV) oxide
were developed by Sumitomo and the first detailed mechanistic study can be found in J. Catal. 255, 29 (2008).
had devised a process to reduce HCl emissions as mandated by the Alkali Act. In this process, hydrogen chloride
is oxidized by oxygen over a copper chloride
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
was no longer the primary product of these plants, and henceforth sold at a loss.
Alkali
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...
s (the initial end product was sodium carbonate
Sodium carbonate
Sodium carbonate , Na2CO3 is a sodium salt of carbonic acid. It most commonly occurs as a crystalline heptahydrate, which readily effloresces to form a white powder, the monohydrate. Sodium carbonate is domestically well-known for its everyday use as a water softener. It can be extracted from the...
) by the Leblanc process
Leblanc process
The Leblanc process was the industrial process for the production of soda ash used throughout the 19th century, named after its inventor, Nicolas Leblanc. It involved two stages: Production of sodium sulfate from sodium chloride, followed by reaction of the sodium sulfate with coal and calcium...
. Hydrogen chloride
Hydrogen chloride
The compound hydrogen chloride has the formula HCl. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric humidity. Hydrogen chloride gas and hydrochloric acid are important in technology and industry...
gas was converted to chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
gas which was then used to manufacture a commercially valuable bleaching powder, and at the same time the emission of waste hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
was curtailed. To some extent this technically sophisticated process superseded the earlier manganese dioxide process.
Invented by Henry Deacon
Henry Deacon (industrialist)
Henry Deacon was a chemist and industrialist who established a chemical factory in Widnes, Lancashire, England.Henry Deacon's father was also named Henry Deacon and his mother was Esther Deacon, his father's cousin. The family were members of the Sandemanian church, one of whose members, Michael...
in 1874. The process was based on this reaction:
- 4HCl + O2 → 2Cl2 + 2H2OWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
The reaction takes place at about 400 to 450 °C in the presence of a copper chloride
Copper(II) chloride
Copper chloride is the chemical compound with the formula CuCl2. This is a light brown solid, which slowly absorbs moisture to form a blue-green dihydrate. The copper chlorides are some of the most common copper compounds, after copper sulfate....
(CuCl2) catalyst. Three companies developed commercial processes for producing chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
based on the Deacon reaction:
- The Kel-Chlor process developed by the M.W. Kellogg Company in the United States.
- The Shell-Chlor process developed by the Shell Oil CompanyShell Oil CompanyShell Oil Company is the United States-based subsidiary of Royal Dutch Shell, a multinational oil company of Anglo Dutch origins, which is amongst the largest oil companies in the world. Approximately 22,000 Shell employees are based in the U.S. The head office in the U.S. is in Houston, Texas...
in the NetherlandsNetherlandsThe Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
. - The MT-Chlor process developed by the Mitsui Toatsu Company in JapanJapanJapan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
.
The Deacon process is now outdated technology. Most chlorine today is produced by using electrolytic process
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 is usually done in bulk using hundreds of sheets of...
es.
However, recent developments with new catalysts based on Ruthenium(IV) oxide
Ruthenium(IV) oxide
Ruthenium oxide is a black chemical compound containing the rare metal ruthenium and oxygen. The most often used O2 catalyst is ruthenium oxide; however, care must be taken since hydrates of this oxide exist....
were developed by Sumitomo and the first detailed mechanistic study can be found in J. Catal. 255, 29 (2008).
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 DeaconHenry Deacon (industrialist)
Henry Deacon was a chemist and industrialist who established a chemical factory in Widnes, Lancashire, England.Henry Deacon's father was also named Henry Deacon and his mother was Esther Deacon, his father's cousin. The family were members of the Sandemanian church, one of whose members, Michael...
had devised a process to reduce HCl emissions as mandated by the Alkali Act. In this process, hydrogen chloride
Hydrogen chloride
The compound hydrogen chloride has the formula HCl. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric humidity. Hydrogen chloride gas and hydrochloric acid are important in technology and industry...
is oxidized by oxygen over a copper chloride
Copper(II) chloride
Copper chloride is the chemical compound with the formula CuCl2. This is a light brown solid, which slowly absorbs moisture to form a blue-green dihydrate. The copper chlorides are some of the most common copper compounds, after copper sulfate....
catalyst, resulting in the production of chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
. This was widely used in the paper and textile industries as a bleaching agent, and as a result sodium carbonate
Sodium carbonate
Sodium carbonate , Na2CO3 is a sodium salt of carbonic acid. It most commonly occurs as a crystalline heptahydrate, which readily effloresces to form a white powder, the monohydrate. Sodium carbonate is domestically well-known for its everyday use as a water softener. It can be extracted from the...
was no longer the primary product of these plants, and henceforth sold at a loss.
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