Oxide bromides

Hydroxyl Compounds. The aqueous chemistry of zirconium is complex, and in the past its understanding was compHcated by differing interpretations. In a study of zirconium oxide chloride and zirconium oxide bromide, the polymeric cation [Zr4(OH)g (H20)jg was identified (189) the earlier postulated moiety [Zr=0] was discarded. In the tetramer, the zirconium atoms are coimected by double hydroxyl bridges (shown without the coordinating water molecules) ... 

Bromine occurs ia the form of bromide ia seawater and ia natural brine deposits (see Chemicals frombrine). Chloride is also present. In all current methods of bromine production, chlorine, which has a higher reduction potential than bromine, is used to oxidize bromide to bromine. 

BrCl can be prepared by the reaction in the gas phase or in aqueous hydrochloric acid solution. In the laboratory, BrCl is prepared by oxidizing bromide salt in a solution containing hydrochloric acid. 

COBr2 has recently been shown to be a useful general brominating reagent for the preparation of d- and f-block bromides and oxide bromides.Thus, when V2O5 is heated with an excess of COBr2 in a sealed Car-ius tube at 125°C for 10 days, a quantitative yield of VOBr2 is obtained by a reaction that is driven thermodynamically by... 

The deposits formed in internal combustion engines by high-octane petrols may be classed as ashes they consist of mixtures of lead oxides, bromides and sulphates derived from the anti-knock additives and, of course, exert their main corrosive effect on the parts operating at the highest temperature the exhaust valves and the sparking-plug electrodes. 

STABREX is easier and simpler to use compared to any other oxidant available for industrial water treatment. The product is pumped directly from returnable transporters (PortaFeed Systems)17 with standard chemical feed equipment. Previously, the only practical ways to apply bromine were to oxidize bromide solutions on-site with chlorine in dual liquid feed systems, or with one of the solid organically-stabilized bromine products applied from sidestream erosion feeders. The former is cumbersome and complex, and the latter is prone to dusting and difficult to control. Other oxidants require complex handling and feed of toxic volatile gases, unstable liquids, multiple-component products, or reactive solids. Simplicity in use results in reduced risk to workers and to the environment. 

Displacement reactions involve one element displacing another element from solution The element that dissolves in the solution is more active than the element supplanted from solution. Within the halogen group the activity decreases from top to bottom. Thus, each halogen is able to displace the members of the group below it, but not those above it. For instance, molecular bromine can oxidize aqueous iodide ion but molecular iodine is incapable of oxidizing bromide ion ... 

Among halogens, chlorine can oxidize bromide and iodide ions in solution under acidic conditions, but not fluoride. For example, it can liberate iodine in... 

Brv does not have the power to oxidize bromide ion beyond the elementary stage. The reaction with bromide ion is ... 

Symons, J.M. and Zheng, M.C.H., Technical note does hydroxyl radical oxidize bromide to bromate /. Am. Water Works Assoc., 89(6), 106-109, 1997. 

Alkyl hydroperoxides, including ethyl hydroperoxide, cuminyl hydroperoxide, and tert-butyl hydroperoxide, are not used by V-BrPO to catalyze bromination reactions [29], These alkyl hydroperoxides have the thermodynamic driving force to oxidize bromide however, they are kinetically slow. Several examples of vanadium(V) alkyl peroxide complexes have been well characterized [63], including [V(v)0(OOR)(oxo-2-oxidophenyl) salicylidenaminato] (R = i-Bu, CMe2Ph), which has been used in the selective oxidation of olefins to epoxides. The synthesis of these compounds seems to require elevated temperatures, and their oxidation under catalytic conditions has not been reported. We have found that alkyl hydroperoxides do not coordinate to vanadate in aqueous solution at neutral pH, conditions under which dihydrogen peroxide readily coordinates to vanadate and vanadium( V) complexes (de la Rosa and Butler, unpublished observations). Thus, the lack of bromoperoxidase reactivity with the alkyl hydroperoxides may arise from slow binding of the alkyl hydroperoxides to V-BrPO. 

Neither V0(02)+ nor V0(02)2 oxidizes bromide rather they associate to form the dinuclear (V0)2(02)3, which oxidizes bromide (Scheme 3) [76], The association constant for the dinuclear compound is rather small (K3 = 9 M at pH 0-2) this explains why it is not observed by 51V NMR at low concentrations of vanadium [73,76], The dinuclear compound has now been observed by 51V NMR at very high concentrations of vanadium [76], A complex of V202(02)3(HGly)2(H20)2 has been isolated in which a p-peroxo coordination of one peroxide is proposed [76],... 

Most other peroxidases are Fe-heme-containing systems, which function as two-electron redox catalysts (Scheme 8). Dihydrogen peroxide oxidizes the Fe-heme moiety by two electrons, forming Compound 1 (a heme + FeIV=0 species) [97], Compound 1 oxidizes the halide ion, forming the active halogenating species. This mechanism cannot be operative in V-BrPO because the vanadium is already in its highest accessible oxidation state. Moreover, native V-BrPO does not oxidize bromide without an acceptable peroxide source. However, it should... 

The haloperoxidases are a class of enzymes that catalyze the oxidation of halides via a reactive peroxometal active site. These enzymes are named according to the most electronegative halide they are able to oxidize. Hence, a bromoperoxidase can oxidize bromide and iodide but not chloride, whereas a chloroperoxidase can oxidize all three. Haloperoxidases are found in most living organisms and predominately fall into two classes the iron heme-based and vanadium-dependent enzymes. Of these, heme-based enzymes are found in mammals, where they provide a vital... 

Interestingly, there is a close structural correspondence between the active sites of the haloperoxidases and the acid phosphatases that allows both peroxidase and phosphatase activity from the two types of enzymes [49-51], For instance, recombinant acid phosphatases from both Shigella flexneri and Salmonella enterica ser. typhimurium, when substituted by vanadate, are able to oxidize bromide when in the presence of hydrogen peroxide. However, the turnover rate is quite slow, which is in accord with the phosphatase active sites not being optimized for peroxidase activity [52],... 

Recall Experiment 11, page 165, which showed that chlorine oxidizes bromide and iodide respectively to free bromine and iodine. The present experiment carries the oxidation still further and raises the valence of each element to +5. 

Yoshida and coworkers47 reported that they readily oxidized bromide and chloride anions into positive halogens with p-nitrobenzenesulfonyl peroxide (equation 26). They found that oxyhalogenated products were formed from the reaction of these positive halogens with olefins, and proposed epihalonium ion intermediates which, in turn, were trapped by oxygen nucleophiles inter- or intramolecularly to afford the oxyhalogenated products (equation 27). 

Nitric acid Hot, fairly concentrated (1 1) nitric acid oxidizes bromides to bromine ... 

By definition enzymes that are able to oxidize chloride, bromide, and iodide are called chloroperoxidases and those able to oxidize bromide and iodide, bromoperoxidases. If a nucleophilic acceptor (RH) is present, a reaction will occur with HOX and halogenated compounds see Halocarbons Halocarbon Complexes) are produced (equation 2). 

Similarly, when vanadate is introduced in the active site of the acid phosphatases, these artificial enzymes are able to oxidize bromide in the presence of H2O2 and to sulfoxidize sulfides in an enantioselective manner. The turnover frequency... 

Lead forms compounds in the +2 and +4 oxidation states. The lead(II) halides, all of which are known, exhibit ionic properties and thus can be assumed to contain Pb2+ ions. Only PbF4 and PbCl4 are known among the possible lead(IV) halides, presumably because lead(IV) oxidizes bromide and iodide ions, producing the lead(II) halide and the free halogen ... 

Sulfuric acid is a moderately strong oxidizing agent, especially at high temperatures. Hot concentrated sulfuric acid oxidizes bromide or iodide ions to elemental bromine or iodine. For example,... 

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