Dow process
Encyclopedia
The Dow process is the electrolytic
Electrolysis
In chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...

 method of bromine
Bromine
Bromine ") is a chemical element with the symbol Br, an atomic number of 35, and an atomic mass of 79.904. It is in the halogen element group. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jerome Balard, in 1825–1826...

 extraction from brine
Brine
Brine is water, saturated or nearly saturated with salt .Brine is used to preserve vegetables, fruit, fish, and meat, in a process known as brining . Brine is also commonly used to age Halloumi and Feta cheeses, or for pickling foodstuffs, as a means of preserving them...

, and was Herbert Henry Dow
Herbert Henry Dow
Herbert Henry Dow was a Canadian born, American chemical industrialist. He is a graduate of Case School of Applied Science in Cleveland, Ohio. His most significant achievement was the founding of the Dow Chemical Company in 1897...

's second revolutionary process for generating bromine commercially.

Also Dow's Process may refer to the hydrolysis of chlorobenzene in the preparation of Phenol.Benzene can be easily converted to chlorobenzene by Electrophillic Aromatic Substitution.After that,dilute Sodium Hydroxide(NaOH) is used at adverse conditions:623Kelvin temperature and 300atmosphere pressure to convert it into a Sodium Phenoxide which can be easily hydrolyzed to form Phenol.This process has now been discontinued at the industrial level.

Before Dow got into 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.

His first process involved eliminating the heating. First he oxidized the bromine with a bleaching agent, then dripped it onto burlap
Burlap
Hessian , or burlap in the US, is a woven fabric usually made from skin of the jute plant or sisal fibres, or may be combined with other vegetable fibres to make rope, nets, and similar products...

, and blew air under the burlap. The air had bromine gas, which was then reacted with iron (or alkalis) producing ferrous bromide.
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