Inorganic bromides

Bromine is used in making fumigants, flameproofing agents, water purification compounds, dyes, medicinals, sanitizers, inorganic bromides for photography, etc. Organic bromides are also important. 

Various ways of overcoming the PTA oxidation problem have been incorporated into commercial processes. The predominant solution is the use of high concentrations of manganese and cobalt ions (2,248—254), optionally with various cocatalysts (204,255,256), in the presence of an organic or inorganic bromide promoter in acetic acid solvent. Operational temperatures are rather high (ca 200°C). A lesser but significant alternative involves isolation of intermediate PTA, conversion to methyl/)-toluate, and recycle to the reactor. The ester is oxidized to monomethyl terephthalate, which is subsequentiy converted to DMT and purified by distillation (248,257—264). 

Another problem arises from brominated aromatic species derived from inorganic bromides used as oxidation cocatalysts. As a result, the cmde NDA is converted to its dimethyl ester, DMNDA [840-65-3] and solvent recrystalHzed to give a high purity diester (36—38). A process for purifying NDA directly by hydrogenation (pure TA process) has also been described (39). 

A considerable amount of hydrobromic acid is consumed in the manufacture of inorganic bromides, as well as in the synthesis of alkyl bromides from alcohols. The acid can also be used to hydrobrominate olefins (qv). The addition can take place by an ionic mechanism, usually in a polar solvent, according to Markownikoff s rule to yield a secondary alkyl bromide. Under the influence of a free-radical catalyst, in aprotic, nonpolar solvents, dry hydrogen bromide reacts with an a-olefin to produce a primary alkyl bromide as the predominant product. Primary alkyl bromides are useful in synthesizing other compounds and are 40—60 times as reactive as the corresponding chlorides (6). 

Anhydrous HBr is available in cylinders (6.8-kg and 68-kg capacity) under its own vapour pressure (24 atm at 25°C) and in lecture bottles (450-g capacity). Its main industrial use is in the manufacture of inorganic bromides and the synthesis of alkyl bromides either from alcohols or by direct addition to alkenes. HBr also catalyses numerous organic reactions. Aqueous HBr (48% and 62%) is available as a corrosive pale-yellow liquid in drums or in large tank trailers (15 0001 and 38 0001). 

Catalytica (ref. 7) have reported a recovery process based on air and catalyst. Whilst the reagent is cheap, the process requires high capital investment. It is a clean process but only treats hydrogen bromide streams and cannot treat inorganic bromide streams directly. 

Jordao, B. A., Yokomizo, Y., Sartori, M. R., De Moraes, R. M., Carvalho, G. R., Medina, J. C., Establishment of levels for inorganic bromide residues in green coffee due to fumigation with methyl bromide, Bol. Inst. Tecnol. Aliment. (Campinas Braz), 60, 41, 1978. (CA92 89255g)... 

Tolerances for residues of inorganic bromides resulting from fumigation with methyl bromide in or on raw agricultural commodities Tolerances for residues of inorganic bromide resulting from soil treatment with combinations of chioropicrin, methyl bromide and propargyl bromide... 

Tolerances of inorganic bromide in processed food as a result of fumigation with methyl bromide Tolerances for residues of inorganic bromide from fumigation with methyl bromide on cereal grains and processed grains used in production of fermented malt beverages... 

Singh G, Rippon LE, Gilbert WS, et al. 1976. Inorganic bromide residue in bananas, bell capsicums (sweet peppers), cherries and apples following fumigation with ethylene dibromide and methyl bromide. Aust J Exp Agric Anim Husb 16 780-784. 

Uses/Sources. Manufacture of organic and inorganic bromides reducing agent, catalyst in oxidations alkylation of aromatic compounds can be generated during the pyrolysis of a variety of materials... 

Hydrobromic acid is used in the preparation of inorganic bromide salts. The acid also is used for many organic syntheses, including alkyl bromides from alcohols or olefins, and bromophenols from phenols. The compound also is used as an acid catalyst in many alkylation, selective oxidation, isomerization, and dehydrogenation reactions. Other apphcations are in extraction of minerals and use as a reducing agent. 

The initial study on the MeO-TEMPO / Mg(N03)2 / NBS triple catalyst system in the oxidation of 1 indicated the necessity of all three components the TEMPO based catalyst, the nitrate source (MNT) and the bromine source (NBS). A large number of metal nitrates and nitrites were screened initially and the highest activity and aldehyde selectivity under comparable reaction conditions were recorded using Mg(N03)2 as the nitrate component. A number of organic and inorganic bromides soluble in HOAc were also screened and high reaction rates were found when NBS was used as the bromide source. The effect of the concentration of the individual components of the new triple catalyst system on the reaction rate, on the conversion of 1 and on the selectivity to 2 over 60 min reaction time is shown in Figure 1. 

Stijve T (1984) Inorganic Bromide in Higher Fungi. Z Naturforsch 39C 863... 

Beernaert and Vandezande [5] developed a gas chromatographic method for the determination of inorganic bromide in vegetables. 

Shiga et al. [14] have described a method for determining total inorganic bromide in crops by HP-LC. 

Part 1 determination of total bromide as inorganic bromide Part 2 determination of bromide. 

Methyl Bromide CH3Br Fumigant insecticide and nematicide Animals/Plants. Metabolism not totally elucidated inorganic bromide ion is formed... 

First results have shown that flame retardants like Tetrabromobisphenol A break down in supercritical water to form carbon dioxide, hydrogen and inorganic bromide. 

Ozone, used as a primary disinfectant, cannot be monitored in drinking-water, because it leaves no residual. Ozonation in the presence of inorganic bromide, which can occur naturally in raw water, can give rise to low concentrations of bromate. The analysis of bromate is difficult and expensive, because a number of other inorganic substances that interfere with the analysis may be present. It is considered, therefore, that routine bromate monitoring is a low priority, and that management should instead involve controlling the conditions of ozonation. Monochloramine... 

Quantification. Gas Chromatography. In blood determined as inorganic bromide, FID—J. Wells and G. Cimbura, J.forens. 5d., 1973,18,437-440. 

Hydrobromic acid is used in the production of inorganic bromides as well as in organic brominations, particularly in the production of pesticides. Some physical properties of the hydrohalide acids are summarized in Table 6. 

Inorganic bromides have been termed catalysts in indirect oxidations —those in which the solution is treated with chlorine or oxidized electrolyt-ically in this type of reaction the bromide is converted to free bromine and then reconverted into bromide. 

Calcium bromide, currently quantitywise the most important inorganic bromide, is utilized in crude oil extraction as a so-called packing fluid or drilling fluid . Packing fluids surround the archimedian screw and equalize the pressure. Depending upon the pressure ratio solutions of sodium ehloride, of mixtures of sodium chloride with sodium carbonate or calcium chloride, of calcium chloride, of mixtures of ealcium chloride and calcium bromide or of mixtures of caleium bromide and zinc bromide (see below) are utilized. Solutions with 53% by weight of calcium bromides are used, which have a density of ca. 1.7 g/mL. 

Bromoform is metabolized in the liver by the mixed function oxidase system (cytochrome P450) to carbon monoxide and bromide. Inorganic bromide has... 

---