COMMERCIAL EXTRACTION OF BROMINE 

 FROM SEA WATER ' 



By Leroy C. Stewart 

 The Dow Chemical Company, Midland, Mich. 



[With 7 plates] 



In 1924 the production of free and chemically combined bromine 

 in this country amounted to approximately 2 million pounds. In 

 1931 this quantity had risen to about 9 million pounds, all of which 

 was being produced from natural brines and from bitterns resulting 

 from evaporation of sea water. This remarkable increase in con- 

 sumption of bromine was due largely to the use of ethylene di- 

 bromide in conjunction with tetraethyllead in the treatment of 

 gasoline motor fuel. 



A number of years ago it became evident that the demand for 

 bromine was becoming so great that its ordinary sources were inade- 

 quate and that new ones would have to be employed. It was logical 

 that sea water should be considered for this purpose, in spite of the 

 fact that its bromine content is less than 70 parts per million, since 

 the enormous quantities of it which are available would insure an 

 inexhaustible source of raw material. It was up to the chemist and 

 engineer, however, to develop a practical and economical method of 

 extracting this desirable halogen element. 



The Ethyl Gasoline Corporation was one of the pioneers along 

 this line. In 1924 they operated a small-scale plant with sea water 

 as its source of bromine and produced tribromoaniline which can be 

 used with tetraethyllead in the treatment of gasoline. Some months 

 later, the same organization operated the process on board a boat, 

 the S. S. Ethyl (4) .- Their method involved the addition of aniline 

 to chlorinated sea water to form tribromoaniline according to the 

 reaction : 



3NaBr + SCl^ + C6H5NH2 — -^ CeH^BrsNHo + 3NaCl + 3HC1 



A number of years ago the Dow Chemical Company likewise 

 undertook the problem of extracting bromine from sea water, but 



^Reprinted by permission from Iiulustiial and Engineering Ctiemistry, vol. 26, p. 361, 

 April 1934. 



2 Numbers in parentheses refer to list of literature cited at end of paper. 



153 



