The chlor-alkali process is an industrial process that uses electrolysis to split a solution of sodium chloride, common salt, into chlorine gas and sodium hydroxide, or caustic soda, two of the chemical industry's most widely used raw materials. The English chemist William Cruikshank first demonstrated chlorine formation from electrolyzed brine around 1800, and Michael Faraday laid out the governing principles of solution electrolysis in 1833, but commercial-scale chlor-alkali production did not begin until 1892. The process runs the reaction two sodium chloride plus two water yields chlorine, hydrogen and two sodium hydroxide, with chloride ions oxidizing into chlorine gas at the anode while water splits into hydrogen gas and hydroxide ions at the cathode; modern plants use ion-selective membranes to keep the products from recombining, and global production had grown to roughly ninety seven million tonnes by 2022.
Facts
SignificanceThe chlor-alkali process became the principal source of industrial chlorine during the twentieth century, simultaneously producing sodium hydroxide, and its output grew from roughly thirty five million tons by 1987 to about ninety seven million tonnes by 2022. 1 FAQs
How do chlor-alkali cells keep the chlorine and caustic soda apart?
Diaphragm cells separate the products with a diaphragm, and mercury cells use a mercury cathode so the sodium hydroxide forms in a separate step.
The chlor-alkali process makes chlorine and sodium hydroxide, also called caustic soda, at the same time by running electricity through salt dissolved in water. Because the two products would react if they met, Britannica describes two main cell designs. A diaphragm cell uses a diaphragm to separate the chlorine and the caustic soda so they cannot mix and react. A mercury cell instead uses a layer of mercury as the cathode, where sodium dissolves in the mercury to form an amalgam that is then reacted with water to give sodium hydroxide and hydrogen.
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In Field
Source Chloralkali Process (Wikipedia)Wikipedia contributors
Sources
1. Chloralkali Process (Wikipedia)
Wikipedia contributors, Wikimedia FoundationHistory section
Industrial scale production began in 1892.
Production scale section
35 million tons of chlorine were prepared by this process
- In Group: Named Industrial Chemical Synthesis Processes, lead paragraph states the chloralkali process is an industrial process for electrolysis of sodium chloride solutions producing chlorine and sodium hydroxide
In Field: Chemical Engineering, Lead section
It is the technology used to produce chlorine and sodium hydroxide (caustic soda), which are commodity chemicals required by industry. 35 million tons of chlorine were prepared by this process in 1987.
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