Metal/bromide

BCl, BBr, and BI undergo exchange reactions to yield mixed boron hahdes. Exchange reactions also occur with trialkyl, triaryl, trialkoxy, or triaryloxy boranes and with diborane. Anhydrous metal bromides and iodides can be prepared by the exchange reaction of the metal chloride or oxide and BBr or BI (21)-... 

Bromine can function as a solvent. One of the very few metal bromides that has significant solubiUty in bromine is cesium bromide, 19.3 g/100 g of solution, thus providing a method of separating cesium bromide from the other alkah bromides (12). Aluminum bromide also is reported to have significant solubiUty in bromine but the pubUshed solubiUty values are not in good agreement (13). Bromine serves as the solvent in some brominations of organic compounds, such as 1,2-diphenylethane (14). 

About 10% is marketed ia elemental form. Eighteen percent is converted to ethylene dibromide [106-93 ] for use ia gasoline and 30% is used ia fire retardants. Fifteen percent is used as a soil fumigant methyl bromide [74-83-9]. Other commercial forms are alkaU metal bromides, ammonium bromide [12124-97-9] and hydrobromic acid [10035-10-6],... 

Terephthalic acid is made by air oxidation of /i-xylene in acetic acid with cobalt and manganese salts of metal bromide at 200 °C and 400 tit. 

Such reactions provide an excellent route to anhydrous metal nitrates, particularly when metal bromides or iodides are used, since then the nitrosyl halide decomposes and this prevents the possible... 

The action of cone H2SO4 on metal bromides or iodides (analogous to the salt-cake process of HCl) causes considerable oxidation of the product HX but cone H3PO4 is satisfactory. Dehydration of the aqueous acids with P2O5 is a viable alternative, DBr and DI are obtained by reaction of D2O on PBr3 and PI3 respectively. 

Brom-jod, n. iodine bromide, -kalium, n. potassium bromide, -kalzium, n., kalk, tn. calcium bromide, -kampher, tn. bromo-camphor, Pharm.) monobromated camphor, -kohlenstoff, tn. carbon (tetra)bromide. -korper, tn. Colloids) "bromide body (bromide ion), -kupfer, n. copper bromide, lauge, /. bromine lye (solution of sodium hypobromite and bromide made by passing bromine into sodium hydroxide solution), -lithium, n. lithium bromide. -Idsung, /. bro-nune solution, -magnesium, n. magnesium bromide. -metall, n. metallic bromide. 

The graphite-metal halides constitute the most populous group of intercalation compounds. Most of the investigative efforts have been directed towards the metal chlorides, particularly FeCls, whereas considerably less is known about the metal bromides S21). Compounds... 

As was noted by Jones (ref. 12) the success of a metal bromide as a catalyst for alkylaromatic autoxidations depends on the ability of the metal to transfer rapidly and efficiently oxidizing power from various autoxidation intermediates onto bromide ion in a manner which generates Br-. The fact that no free bromine is observable in this system is consistent with rapid reaction of intermediate bromine atoms with the substrate. Inhibition of the reaction by cupric salts can be explained by the rapid removal of Br2 or ArCH2- via one-electron oxidation by Cu (Fig. 10). 

Interaction of lead oxide with bromide salts in phenol at the ratio Br PbO less than 2 yields the precipitation of white sediments with the general formula PbnOm(OPh)(2.z)(n-m)Brz(n-m), where n = 4 - 10, m = 1 - 4, z = 0 - 1 and formation of (n-m) moles of water. Reaction takes place in the presence of a variety of bromide salts including quaternary and alkali metal bromides. In the latter case, the presence of acoordinating solvent, e.g. MeCN, is necessary. The composition of product lead bromophenoxides depends on the Br PbO ratio, bromide salt and solvent. These complexes usually have Pb 0 ratio of 4 1 or 3 1, and variable levels of bromide (including some bromide-free complexes) (Table 3). 

Metal bromides, 4 322-330 Metal can food packaging, 18 37-39 Metal-carbene complexes, 26 926 Metal-carbon compounds, 4 648, 650 Metal-carbon eutectic fixed points, 24 454 Metal carbonyl catalysts, supported, 16 75 Metal carbonyl complexes, 16 73 Metal carbonyls, 15 570 16 58-78 bonding and structure of, 16 59-64 from carbon monoxide, 5 12 in catalysis, 16 72-75 economic aspects of, 16 71 health and safety aspects of, 16 71 heteronuclear, 16 69-71 high nuclearity, 16 66-69 high nuclearity carbonyl clusters, 16 64-66... 

It is known that the oxidation of alkyl-substituted aromatic hydrocarbons in acetic acid on metal bromide catalysis follows the one-electron transfer mechanism (Sheldon and Kochi 1981). The rate-determining stage is the one-electron transfer from the substrate to the metal ion in the highest oxidation state (Digurov et al. 1986). As a result, an unstable cation-radical is formed that... 

Kricheldorf HR, Sumbel MV (1988) Polylactones, 15. Reactions of 5-valerolactone and E-caprolactone with acidic metal bromides. Makromol Chem 185 317-331... 

It also may be obtained by double decompostion reactions between a ferric salt and a bromide (alkali metal bromide) in aqueous solution followed by evaporation and crystallization ... 

Hydrobromic acid reduces sulphuric add to sulphur dioxide, as also does hydriodic acid, but with the latter in high concentration the reduction goes further, producing sulphur and hydrogen sulphide.2 For this reason when metallic bromides and iodides are treated with sulphuric acid, the halogen element is liberated, the temperature at which this becomes evident depending on the concentration of the acid thus, with the potassium salts, the following observations have been made 3... 

The majority of the metals react with selenium oxybromide with the production of the corresponding metal bromides, selenium dioxide and selenium monobromide. Zinc, cadmium, chromium, nickel, cobalt, tungsten and tantalum, however, are not attacked even after prolonged heating at 100° C. 

Heavy metal compounds tend to be toxic and require careful handling some of those are compounds of lead, thallium, mercury, and barium. Provide the formulas of these heavy metal bromides, sulfides, nitrides, and carbonates. The more common oxidation numbers of the metals having more than one are Pb2+, T1+, Hg2+. 

Terephthalic acid (boiling point 300°C) and dimethyl terephthalate (melting point 141°C) are derived from p-xylene by oxidation of p-xylene in acetic acid as a solvent in the presence of a variety of catalysts such as cobalt and manganese salts of heavy metal bromides as catalysts at 200°C and 400 psi (Fig. 1). 

The reversible190 exchange of alkyl chlorides with metal bromides in a two-phase system, under PTC, has been reported to depend on the nature of the metal cation and the concentration of the aqueous phase. Most effective bromide donors are lithium191 and calcium bromides192 particularly when applied in the presence of a small amount of water. Interestingly, both the equilibrium composition and the rate in the reaction of various alkali and alkali earth bromides with -octyl chloride catalyzed by tetra- -hexylammonium bromide are strongly dependent on the amount of water present in the system193,194. 

Troyanov et al. have also reported the synthesis of Ba5(thd)9Cl(H20)7181 and Na2Ba7(thd)2(pivalate)]4(py)4(H20)2181 by reaction of BaCI2 2H20 with the sodium derivative of the ligands. The alkaline-earth metal bromides have been used in the synthesis of M(tdfnd)2 H20 and M(dfhd)2 H20.16° The generalized reaction is shown in Eq. (18). One drawback of these reactions is that they usually yield hydrated compounds. However, it has been shown that tdfnd compounds can be dehydrated by sublimation.161... 

Partenheimer W. The aerobic oxidative cleavage of lignin to produce hydroxyaromatic benzaldehydes and carboxylic acids via metal/bromide catalysts in acetic acid/water mixtures. Adv Synth Catal. 2009 351 456-66. 

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