Bromate, reaction with bromide

The [H+] term in bromate reactions referred to above has been confirmed in the reaction with bromide. A similar observation has been made in the reaction with the mercuryfi) dimer species. In this case the mechanism is... 

Bancroft and Gesser [870] conclude that kinetic factors are predominant in determining whether decomposition of a metal bromate yields residual bromide or oxide. The thermal stabilities of the lanthanide bromates [877] and iodates [877,878] decrease with increase in cationic charge density, presumably as a consequence of increased anionic polarization. Other reports in the literature concern the reactions of bromates of Ag, Ni and Zn [870] and iodates of Cd, Co, Mn, Hg, Zn [871], Co and Ni [872], Ag [864], Cu [867], Fe [879], Pb [880] andTl [874]. 

Unlike chlorine and fluorine, the free bromine and iodine are produced by chemical methods (reaction of chlorine with bromide or iodide solutions). Electrochemical methods are used to produce the salts of their oxygen-containing acids, the bromates and iodates, from the corresponding bromide and iodide solutions. These reactions are analogous to those in chlorate production [Eqs. (15.31) to (15.34)] and involve the intermediate formation of hypobromites and hypoiodites. 

Among the most important indirect methods of analysis which employ redox reactions are the bromination procedures for the determination of aromatic amines, phenols, and other compounds which undergo stoichiometric bromine substitution or addition. Bromine may be liberated quantitatively by the acidification of a bromate-bromide solution mixed with the sample. The excess, unreacted bromine can then be determined by reaction with iodide ions to liberate iodine, followed by titration of the iodine with sodium thiosulphate. An interesting extension of the bromination method employs 8-hydroxyquinoline (oxine) to effect a separation of a metal by solvent extraction or precipitation. The metal-oxine complex can then be determined by bromine substitution. 

The Ru(m)-catalyzed oxidation of glycerol by an acidified solution of bromate (BrCfi ) at 45 °C consumes the required amount of 2 moles of bromate to obtain pure glyceric acid. Traces of Hg(OAc)2 were used as scavenger for potentially formed bromide, thereby eliminating the formation of bromine (formed by reaction of bromide and bromate) as an alternative oxidant [96]. The reaction is first order in Ru(m) (0.58 ms-1 at 45 °C) and zero order in substrate and protons. The addition of RuC163 to protonated bromate is assumed to be rate limiting. Similar catalytic chemistry is obtained with Rh(m)Cl3 [97]. 

Uracils and related pyrimidines undergo oxidative addition to the 5,6-double bond, and the reaction with a number of oxidants to form 5,6-epoxides and 5,6-diols was discussed in CHEC-II(1996) <1996CHEC-II(6)93>. Oxidative halogenation can also occur <1996SC3583, 1998NN1125>, as shown by the formation of 5-bromo-5,6-dihydro-6-methoxyuracil 100 from uracil 99 by treatment with a mixture of potassium bromate and potassium bromide in the presence of Dowex ion-exchange resin in methanol <1996SC3583>. 

The liberated bromine is carried from the tower by means of a stream of air and into an absorber containing sodium carbonate solution. By reaction with sodium carbonate, the bromine is converted to sodium bromide and sodium bromate ... 

How does dilute H2SO4 react with a pure bromate Explain, with reactions, the test for the presence of bromate in the bromide. 

In a similar manner potassium bromide yields bromine and potassium hydroxide, but the further formation of hypobronute and bromate is less rapid than the analogous reaction with potassium iodide.4... 

The reaction of bromate with bromide ion was reported, as early as 1898, as obeying the rate expression ... 

Bromate itself reacts only slowly with reductants the reactive substance is Br2 formed according to (20-9), BrCl, or a mixture of BrCl and CI2 formed in solutions containing chloride. The electrode potential is controlled by the halide concentration, and the reaction is slow in the absence of both chloride and bromide. In (20-9) the rate of reaction is proportional to bromate ion concentration, bromide ion concentration, and hydrogen ion concentration squared. ... 

Bromine is a volatile liquid at room temperature and pressure and so cannot be measured accurately by pipette. It is also an extremely corrosive compound, irritant to eyes, lungs and mucous membranes. To overcome these difficulties, the bromine required for reaction with the resorcinol is generated in situ by reaction of potassium bromate and potassium bromide in the presence of strong mineral acid. 

Lactones have been converted to (hydroxyalkyljcyclopropyl phenyl ketones on reaction with phenylmagnesium bromide and phenyllithium. Reductive dimerization of ethyl cyclo-propanecarboxylate with sodium gave l,2-dicyclopropylethane-l,2-dione in 69% yield when thionyl chloride treatment was carried out prior to hydrolytic workup, and to dicyclopropyl ketone in 74% yield, when workup included sodium bromate treatment. A related reaction occurred during thermolysis of 6,6-dimethyl-5,7-dioxaspiro[2.5]octane-4,8-dione to give dispiro[2.1.2.1. ]octane-4,8-dione. ... 

It is shown in Field, Koros and Noyes (1972) that (Rl) is related to the reaction of bromate with bromide in acid to give bromine... 

Original B-Z reaction where metal ion catalyzed organic substrate is brominated by enolization and bromide is liberated when the organic bromate reacts with the oxidized form of the catalyst, [See G G]. 

CALCIUM BROMATE (10102-75-7) A strong oxidizer. Violent reaction with combustible materials, reducing agents. Contact with strong acids forms hydrogen bromide. Incompatible with aluminum, ammonium salts, arsenic, carbon, copper, metal powder, organic matter, sulfides, sulfur, phosphorus. 

All the component reactions investigated are found to be exothermic. Initial temperature rise of bromide + bromate reaction was found to be the highest (0.55°C/min) while that of cerous + bromate + malonic acid was to be found to be quite low (0.085°C/min). Thus in the first stage, when the reaction was mixed, the latter reaction involving autocatalysis predominates and the temperature rise is very slow. On the other hand, when Br + BrOj reaction involving inhibition reaction becomes dominant, there is a sharp rise in temperature. The thermochemical behaviour is thus in conformity with the FKN mechanism (Br -control mechanism). 

This method, very common in the analytical literature, gives an amplification factor of 6 and is the basis of a large number of amplification reactions. It can be applied using different oxidants, such as chlorine or bromine wateq or sodium hypochlorite. A method has been proposed for the simultaneous determination of iodide and bromide ions, and also for the determination of iodine and bromine in organic compormds. The method is based on the oxidation of both ions to their halates and titration of the iodate and bromate after reaction with iodide for... 

In aquation of the cations [M(NH3)5Br] + (M = Cr or Co) in alcohol-water mixtures, solvent composition variation has much more effect on A.S than on iiH. This is attributed to solvation-shell ordering effects in the transition state. Enhancement of reactivity in the reaction of cobalt(ii) with chlorophyllic acid in methanol on addition of lithium nitrate is attributed to inhibition of transition-state solvation. The effective radius of a transition state can be guessed from the variation of rate constant with dielectric constant. This approach has been used for the bromide-bromate reaction. In contrast to this concentration of attention on the transition state, it may be noted that it is the stabilization of the reactant in relation to water structure that is thought to control the variation of the racemization rate of the ( + )-[Co(phen)3] + cation in t-butyl alcohol-water mixtures. ... 

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