Formation Of Bromine Research Articles

The Influence of Bromide Ion on Organic Chlorine and Organic Bromine Formation During Free Chlorination

The influence of bromide ion on the formation of nonpurgeable organic bromine and nonpurgeable organic chlorine was not studied previously because no analytical technique existed that could separately measure total organic chlorine and total organic bromine. This measurement has been made possible with the application of the neutron activation analysis. Thus, this study determined the influence of bromide ion concentrations on the relative amounts of nonpurgeable organic chlorine and bromine and chlorine‐substituted and bromine‐substituted trihalomethanes formed during the free chlorination of drinking water over various reaction times and pH values. Measurements of this type are important because bromide ion concentrations are not lowered by conventional drinking water treatment processes, bromide ion is present in many groundwaters, bromide ion may increase the production of trihalomethanes, and the health effects of bromine‐substituted compounds may be different from those of their chlorine‐substituted counterparts.

Corrosion problems caused by bromine formation in additive dosed MSF desalination plants

Failures of type 316L stainless steel components in the venting system of MSF desalination plants in Qatar were found to be due to bromine. This paper describes the failures and the investigation which led to the identification of bromine as the agent causing corrosion. It also describes the experimental work leading to an explanation of the mechanism by which bromine compounds can be evolved from chlorinated seawater. The presence of ammonia in seawater is necessary for this to occur in an additive dosed plant. Remedial action to prevent corrosion problems in the venting system are discussed.

Corrosion problems caused by bromine formation in MSF desalination plants

The chlorination of sea water has been considered in detail, with particular reference to the oxidation of bromide ions, already present in sea water, to bromine by the chlorine. It has been shown that under normal conditions of sea water chlorination the bromide ions will rapidly be oxidised to bromine, hypobromous acid and hypobromite ion, bromine being the predominant form at pH values of 6 and less. The significance of this work to MSF desalination plants is that acid treated plants provide conditions suitable for bromine gas formation in the decarbonator and deaerator. It has been calculated that for such plants operating with residual chlorine levels in the range 0.2 to 0.5 ppm the condansates from the steam that has passed through the deaerator into the vent system could well contain between 10–100 ppm Br 2; these levels of bromine can cause severe localised corrosion problems with conventional stainless steels. Such corrosion has been observed in practice. Calculations indicate that providing the pH is 6 and the residual chlorine is <0.2 ppm at the point of entry to the deaerator, the likely bromine level in the condensate in the vent system will be <10 ppm, and this may well be low enough to prevent corrosion of type 316 stainless steel.

Photooxidation of tetrathiatetracene and tetraselenatetracene in halocarbon solutions: formation of new radical-cation salts

The photooxidation of tetrathiatetracene TTT and its selenium analogue TSeT to halocarbon solutions by visible and UV irradiation have been studied. This reaction leads to the formation of new chlorine, bromine, and iodine radical-cation salts which have been characterized.

Halogen discharge on graphite electrodes from silver halide solid electrolytes

Halogen ion discharge from the solid electrolytes AgI, AgBr, and 2Me4NI · 13 AgI on pressed-powder graphite electrodes at room temperature was examined by cyclic voltammetry on Ag¦AgX¦C solid state cells. Iodine discharge from AgI occurs rapidly, reversibly, and with a moderate ‘undervoltage’ ascribable to iodine monolayer buildup. Bromine discharge from AgBr is strongly irreversible and was seen to occur in two stages; a small, permanently saturable discharge attributed to direct formation of bromine-graphite ‘residue’ compounds, and a steady-state main discharge attributed to formation and fast diffusion of bromine in interlamellar graphite compounds. Iodine discharge from 2Me4NI · 13 AgI appears to occur via the formation of Me4NI3. On continuous 0–500mV voltammetric cycling, incomplete electrolyte recombination leads first to a new iodine discharge reaction and finally to cessation of Faradaic activity.

Kinetics of oxidation of hydrobromic acid by nitric acid in the presence of nitrous acid

The rate of formation of bromine on treating nitric acid with hydrobromic acid has been investigated at 2, 25, and 50 °C. The order of reaction is 1·5 with respect to nitrous acid and between 1 and 2 with respect to bromide ion. The rate is strongly dependent on acid and neutral salt concentrations, but the influence of nitrate-ion concentration is small. A proposed mechanism, in accord with the data, is based on fast equilibria forming an intermediate which reacts further in a slow step. The equilibria are reversed by high water concentrations; cations, by hydration, reduce the water concentration and increase the rate. Hydration numbers of salts can be calculated from this increase in rate.

Interaction of N-vinylbenztriazole with halogens and hydrogen halides

1. In the interaction of N-vinylbenztriazole with bromine, there is a simultaneous complex formation and addition of bromine at the vinyl group. 2. In the chlorination of N-vinylbenztriazole, chiefly the product ofα,β-addition is formed. 3. Hydrohalogenation of N-vinylbenztriazole is accompanied only by a process of complex formation.

Hot-Atom Chemistry of Bromine. IV. Chemical Effects of 81Br(n,γ)82gBr, 81Br(n,γ)82mBr and 82mBr(I. T.)82Br Excitation in Antimony Tribromide and Benzene System

Abstract Antimony tribromide and a molecular compound between antimony tribromide and benzene (2:1) have been irradiated to provide 82mBr sources. The results obtained by the dissolution of the irradiated molecular compound, by means of which technique the chemical effects of 81Br(n,γ)82gBr and 82mBr(I.T.)82Br were determined separately, had shown very low organic yields from either (n,γ) or (I.T.) excitation. The reaction of 82mBr(I.T.)82Br in benzene showed a growth in the organic yields. Moreover, the organic yield of 82Br was lower when the system was frozen than when it was stored as a liquid. These results are explained by assuming that, in the frozen system, the antimony tribromide (82mBr) forms a molecular compound with the benzene. The higher organic yields in the frozen systems than those in the molecular compound itself must be due to the formation of free bromine (82mBr), which turns out to be an organic radiobromide. The hydrolytic behavior of the irradiated antimony tribromide and the molecular compound supports the idea of the presence of free bromine (82mBr) at the end of the irradiation.

Autoxidation of p-toluic acid catalyzed by cobalt bromide

The liquid-phase autoxidation of p-xylene proceeds with comparative ease in the presence of cobalt or manganese salts at 100–130°C to p-toluic acid. The oxidation of p-xylene to terephthalic acid in high yield may be achieved by using the cobalt or manganese salt in combination with an inorganic bromide. The present study, which was directed towards the elucidation of the latter reaction, was confined to the second part of the reaction, namely, the oxidation of p-toluic acid catalyzed by cobalt bromide. The reaction was observed to occur in glacial acetic acid at 90°C in two well-defined stages each of which was investigated. The first stage involved catalysis by both cobalt and bromide and during this phase of the oxidation bromide was present in the ionic form. The rate was proportional to the [cobalt][bromide] and independent of the substrate concentration above a limiting value and of the oxygen pressure in the range 2–32 cm Hg. At the onset of the second stage of the reaction the bromide ion was absent and the reaction was catalyzed by cobalt salt and p-bromomethyl benzoic acid. The principal intermediate in both stages was terephthaldehydic acid. Initiation occurred by the formation of atomic bromine either by direct electron transfer between cobaltic and bromide ions or by reaction of hydroperoxides with Br– or HBr. The aldehydic intermediate and final acid were formed from peroxidic intermediates.

Effects of Ligands in the Cobalt Salt-catalyzed Decomposition of t-Butyl Hydroperoxide

Abstract A kinetic study has been made of the cobalt acetate-catalyzed decomposition of t-butyl hydroperoxide in acetic acid at 40.4°C, and the effects of added lithium salts on the decomposition rate have been studied. The observed rate law for the cobalt acetate-catalyzed decomposition is: v=k2[Co(II)][t-C4H9OOH]+k3[Co(II)]2[t-C4H9OOH]. When lithium halides (chloride and bromide) are added to this system, the cobalt acetate is changed to cobaltous halide and the rate of decomposition is markedly decreased. In the case of lithium bromide the hydroperoxide decomposition is accompanied by the generation of molecular bromine. The mechanisms for the bromine formation will be discussed. The role of these cobalt salts in the course of autoxidation in relation to the hydroperoxide decomposition will also be discussed.

The radiolytic formation of tetravalent bromine and its reactions with halide ions and halogens

The formation of tetravalent bromine as a result of the reduction of bromate ions by radiolytically produced hydrated electrons and hydrogen atoms has been investigated in the iodide-bromate system. BrO 3 2− (or BrO 2) may react both as an oxidant or as a reductant. BrO 3 2− was found to oxidize iodide and bromide in an acid catalysed reaction. The reactions of BrO 3 2− with I 2 and Br 2 to give BrO 3 − + I 2 − and Br 2 − demonstrate the reducing properties of tetravalent bromine.

Homolytic reactions of tetraethyltin with propyl bromide

1. The photochemical reaction between tetraethyltin and propyl bromide goes by a free radical chain mechanism. As well as bromotriethyltin, ethane, ethylene, propane, and propene are formed, and the relative amounts of these depend on the proportions of the reactants taken. 2. The same type of reaction is found in that initiated by benzoyl peroxide between tetraethyltin and propyl bromide. 3. In the free-radical reactions of benzoyl peroxide with propyl bromide and with 1,2-dibromoethane the latter are hydrogen donors and only to a small extent bromine-donors. The secondary CH2CHCH2Br and CHBrCH2Br radicals formed break down with formation of atomic bromine and the corresponding olefin.

The bromination of swimming pools.

DURING the course of an investigation upon the chlorination of sea water swimming pools, it was found that the liberation of bromine from the naturally occurring bromide, which is normally present to the extent of 70 ppm, caused the formation of bromamines as well as chloramines in the presence of nitrogenous matter from the bathing load. A study was made of the chemistry of these bromamines and their bactericidal action, and it was felt that the information so obtained should he made available in a condensed form to those who use bromine to sterilize the water of swimming pools, and to possibly encourage the extension of its use. Bromine has been used for the sterilization of pools in Illinois' and is referred to in the official publication of the American Public Health Association on Swimming Pools and Other Bathing Places,2 in which a request is made for further investigations upon the use of this element for such purposes. A limitation on the use of bromine for sterilizing in pools has been the lack of knowledge of the behavior of this element in its reactions with ammonia and the resultant formation of combined bromine, as in the reaction of chlorine with ammonia yielding chloramines together with the well known break point reaction. A further difficulty has been the lack of methods to determine whether or not a residual due to bromine was free bromine or bromamine, i.e., combined bromine. These problems have been overcome in the author's laboratory and it is the object of this paper to outline the bactericidal effects, analytical chemistry, and the reactions of free and combined bromine in swimming pools.

New contributions to the study of the halogenating effect of iodine bromide

It was found that iodine bromide has exclusively an iodinating effect in an aqueous solution, in the presence of elementary iodine (of non interhalogen nature). The small homolytic dissociation of iodine bromide is suppressed by iodine. In this way the formation of elementary bromine is inhibited. Consequently, in suitable conditions the brominating effect of iodine bromide is suspended. The degree of homolytic dissociation of solutions of iodine bromide of various composition at room temperature was established.

The Existence of Different Capture Levels in the Formation of Nuclear Isomers by Slow Neutron Irradiation

Experiments have been performed on the formation of bromine and rhodium isomers, by thermal as well as resonance neutrons, in order to study capture levels. With slow neutrons of variable energies obtained from a Ra-Be source in a slowing-down medium of paraffin, we have studied: (a) the relative formation of the isomeric pairs as a function of the distance from the source and (b) the migration distances for each isomer.The experimental results show that for bromine isomers produced by resonance neutrons as well as for rhodium isomers produced by resonance and $C$-neutrons, the ratio of the activities of the fundamental state to the metastable state is a function of the distance from the source. Moreover, at each point this ratio is different for resonance and for $C$-neutrons. The migration distances corresponding to each of the isomers formed by resonance neutrons on bromine, or by $C$-neutrons on rhodium, are found to be different.This leads to the assumption of the existence of more than one capture level in the formation of the bromine and rhodium isomers. It may be suggested that for rhodium the resonance levels extend within the region defined by the $C$-neutrons.

Scientific Serials

Journal of the Russian Chemical and Physical Society, vol. xvi. fasc. 6.—On the succession of reactions, by M. Lvoff, being an introduction into a series of researches undertaken by the author and several students, in order to disclose the mechanism of polymerisation.—On the action of chlorine on butylenes, by M. Chechoukoff.—On constants of chemical affinity, by W. Ostwald. The author, who maintains the views of Berthollet, further elaborated by Guldberg and Waage, considers that there is, for each body, a certain numerical coefficient of its chemical affinities as characteristic for the body as its atomic weight; and in addition to his former works, already published in the Journal für pract. Chemie, he publishes now a preliminary list of “constants of chemical reactions.”—On glycidic acids, by P. Melikoff.—On the displacement of chlorine by bromine, and an explanation of the reactions which are accompanied by a disengagement of heat, by A. Potylitzin. The substitution of chlorine by bromine, in seeming contradiction with the law of maximum work, and which Berthelot has endeavoured to explain by the formation of chloric bromine and bromides of metals, could be explained by admitting that the reaction is going on with the heat received from the surrounding medium. This important inquiry, pursued by the author for several years past, brings him to interesting conclusions on thermo-chemistry.—On asarone, by MM. Rizza and A. Butlcroff, being an inquiry into the properties of the camphor received from Asarum europæum,—On a new apparatus for determining specific heat, by W. Loughinin. It is a modification of the apparatus of Neumann.—On the reduction of isodinitrobenzyl, by P. Goloubeff.—On the preparation of animal colouring matters from albuminoid substances, by W. Mikhailoff.—On azophcnylacetic acid, note by M. Wittenberg.—On the solution of lithium carbonate in water, note by J. Bevad.—On a hygienic photometer for schools, by Prof. Petroushevky. It allows the amount of light received by books, paper, &c., on the desks of scholars, to be rapidly and accurately measured.—On the volume of a liquid considered as a function of temperature under a constant pressure, by K. Jouk. Diethyl-amine and ethyl chloride both agree with Prof. Avenarius's formula: v = a + b log (π - t).—On the relation between pressure and the density of rarefied gases; preliminary communication by K. Kraevitch.—Notes on the structure of the atmosphere, by MM. Stankevitch and Kogovsky.