GB285915A - An improved process for preparing metal bromides - Google Patents

Abstract

285,915. Meulen, J. H. van der. Feb. 25, 1927, [Convention date]. Sodium, potassium, and calcium bromides; metallic bromides in general. - Bromides free from hypobromites or bromates are produced by reacting metallic oxides, hydroxides, carbonates or bicarbonates with bromine in the presence of water and of reducing agents the decomposition of which gives rise only to water and gases. Alternatively, the reducing agent may contain also the metal of which the bromide is required, in which case it may replace wholly or in part the oxide &c. to be used. As reducing agents may be used uraa, cyanamide, ammonium carbonate or bicarbonate, formamide, carbamates, ammonium cyanide, or easily decomposed organic acids such as formic or oxalic acid or ammonium or metal compounds thereof, or calcium nitride. Examples relate to the production of sodium bromide from bromine and sodium carbonate in presence of urea, and from bromine and a mixture of sodium carbonate and formate; and of calcium bromide from bromine and a mixture of calcium carbonate and formate. The bromide may be crystallized out by evaporating the solution obtained, and the mother-liquor be used in a fresh operation. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the following subject-matter :-Instead of being crystallized, the bromide may be salted out, e.g. in the case of using potassium or sodium carbonate to produce the corresponding bromide, by the addition of the corresponding carbonate, whereafter on adding bromine to the remaining liquor, the process may be continued. Ammonia and hexamethylenetetramine are also specified as reducing agents. This subject-matter does not appear in the Specification as accepted.