Dow process (bromine): Difference between revisions

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The patents doesn't state that the process is exclusively electrolytic
 
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{{For|other Dow processes|Dow process (disambiguation)}}
{{For|other Dow processes|Dow process (disambiguation)}}
The '''Dow process''' is the [[electrolysis|electrolytic]] method of [[bromine]] extraction from [[brine]], and was [[Herbert Henry Dow]]'s second revolutionary process for generating bromine commercially.
The '''Dow process''' is the method of [[bromine]] extraction from [[brine]], and was [[Herbert Henry Dow]]'s second revolutionary process for generating bromine commercially.


This process was patented in 1891. In the original invention, bromide-containing brines are treated with [[sulfuric acid]] and [[bleaching powder]] to oxidize bromide to bromine, which remains dissolved in the water. The aqueous solution is dripped onto burlap, and air is blown through causing bromine to volatilize. Bromine is trapped with [[iron]] turnings to give a solution of [[ferric bromide]]. Treatment with more iron metal converted the ferric bromide to [[ferrous bromide]] via [[comproportionation]]. Where desired, free bromine may be obtained by thermal decomposition of ferrous bromide.<ref>{{cite patent | country = US | number = 460370 | inventor = H. H. Dow | title = Process of Extracting Bromine | gdate = 1891-09-29}}</ref>
This process was patented in 1891. In the original invention, bromide-containing brines are treated with [[sulfuric acid]] and [[bleaching powder]] to oxidize bromide to bromine, which remains dissolved in the water. Other oxidizers, such as electric current or [[chlorine]], may be used instead of bleach. The aqueous solution is dripped onto burlap, and air is blown through causing bromine to volatilize. Bromine is trapped with [[iron]] turnings to give a solution of [[ferric bromide]]. Treatment with more iron metal converted the ferric bromide to [[ferrous bromide]] via [[comproportionation]]. Where desired, free bromine may be obtained by thermal decomposition of ferrous bromide.<ref>{{cite patent | country = US | number = 460370 | inventor = H. H. Dow | title = Process of Extracting Bromine | gdate = 1891-09-29}}</ref>


Before Dow entered the bromine business, brine was evaporated by heating with wood scraps and then crystallized [[sodium chloride]] was removed. An oxidizing agent was added, and bromine was formed in the solution. Then bromine was distilled.  This was a very complicated and costly process.
Before Dow entered the bromine business, brine was evaporated by heating with wood scraps and then crystallized [[sodium chloride]] was removed. An oxidizing agent was added, and bromine was formed in the solution. Then bromine was distilled.  This was a very complicated and costly process.

Latest revision as of 03:21, 30 June 2025

Script error: No such module "For". The Dow process is the method of bromine extraction from brine, and was Herbert Henry Dow's second revolutionary process for generating bromine commercially.

This process was patented in 1891. In the original invention, bromide-containing brines are treated with sulfuric acid and bleaching powder to oxidize bromide to bromine, which remains dissolved in the water. Other oxidizers, such as electric current or chlorine, may be used instead of bleach. The aqueous solution is dripped onto burlap, and air is blown through causing bromine to volatilize. Bromine is trapped with iron turnings to give a solution of ferric bromide. Treatment with more iron metal converted the ferric bromide to ferrous bromide via comproportionation. Where desired, free bromine may be obtained by thermal decomposition of ferrous bromide.[1]

Before Dow entered the bromine business, brine was evaporated by heating with wood scraps and then crystallized sodium chloride was removed. An oxidizing agent was added, and bromine was formed in the solution. Then bromine was distilled. This was a very complicated and costly process.

References

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