BrCl

Chlorine also forms BrCl (see bromine halides) and ICl and ICI3 (see iodine chlorides). See also inierhalogen compounds. 

C3H3CI c241 C3H( BrCl b307 C3H8N2S d705... 

Bromination of sulfolane by BrCl under uv irradiation gives 2-bromosulfolane [29325-66 ] which reacts further to give i7j -2,5-dibroniosulfolane [30186-52-8] (5). Continued irradiation converts the <7j -isomer to /n j -2,5-dibroniosulfolane [30186-54-0] which yields first the trans-2 4 isomer [30186-53-9] and then the trans-2 4 isomer [15091 -30-2] upon further irradiation. 

BrCl is prepared by the addition of equivalent amounts of chlorine to bromine until the solution has increased in weight by 44.3 percent The reaction is as follows ... 

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. 

BrCl exists in equilibrium with bromine and chlorine in both gas and liquid phases. Table 5 lists various physical properties of BrCl. Due to the polarity of BrCl, it shows greater solubility than bromine in polar solvents. In water, it has a solubility of 8.5 gms per 100 gms of water at 20 C (that is, 2.5 times the solubility of bromine 11 times that of chlorine). Bromine chloride s solubility in water is increased greatly by adding chloride ions to form the complex chlorobromate ion, BrCl 2. 

It should be noted that although BrCl is mainly a brominating agent that is eompetitive with bromine, its ehemieal reaetivity makes its action similar to that of ehlorine (that is, disinfection, oxidation, and a bleaching agent). BrCl hydrolyzes exelusively to hypobromous aeid, and if any hydrobromie aeid (HBr) is formed by hydrolysis of the dissociated bromine, it quickly oxidizes to hydrobromous acid via hypochlorous acid. 

Since hypohalous acid is a much more active disinfectant than the hypohalite ion, the effect of pH on ionization becomes important. Hypobromous acid has a lower ionization value than hypochlorous acid and this contributes to the higher disinfectant activity of BrCl compared with chlorine. 

The major organic reactions of BrCl consist of electrophilic brominations of aromatic compounds. Many aromatic compounds do not react in aqueous solution unless the reaction involves activated aromatic compounds (an example being phenol). Bromine chloride undergoes free-radical reactions more readily than bromine. 

Metal ions in their reduced state also undergo reactions with BrCl. Examples include iron and manganese. 

Bromine chloride s reactivity with metals is not as great as that of bromine however, it is comparable to chlorine. Dry BrCl is typically two orders of magnitude less reactive with metals than dry bromine. Most BrCI is less corrosive than bromine. Like chlorine, BrCl is stored and shipped in steel containers. Also, Kynar and Viton plastics and Teflon are preferred over polyvinyl chloride (PVC) when BrCl is in the liquid or vapor states. 

The elusive NBr3 was finally prepared as a deep-red, very temperature-sensitive, volatile solid by the low-temperature bromination of bistrimethylsilylbromamine with BrCl ... 

All six possible diatomic compounds between F, Cl, Br and I are known. Indeed, ICl was first made (independently) by J. L. Gay Lussac and H. Davy in 1813-4 soon after the isolation of the parent halogens themselves, and its existence led J. von Liebig to miss the discovery of the new element bromine, which has similar properties (p. 794). The compounds vary considerably in thermal stability CIF is extremely robust ICl and IBr are moderately stable and can be obtained in very pure crystalline form at room temperature BrCl readily dissociates reversibly into its... 

In general the compounds have properties intermediate between those of the parent halogens, though a combination of aggressive chemical reactivity and/or thermal instability militates against the determination of physical properties such as mp, bp, etc., in some instances. However, even for such highly dissociated species as BrCl, precise molecular (as distinct from bulk) properties can be determined by spectroscopic techniques. Table 17.12 summarizes some of the more important physical properties of the... 

Cl-I-Br] the I-Cl distance is greater than the I-Br distance, and in [Br-I-I] I-Br is greater than I-I. On dissociation, the polyhalide yields the solid monohalide corresponding to the smaller of the halogens present, e.g. CsIClj gives CsCl and ICl rather than Csl + Clj. Likewise for CsIBrCl the favoured products are CsCl(s) + IBr(g) rather than CsBr(s) + ICl(g) or Csl(s) + BrCl(g). Thermochemical cycles have been developed to interpret these results. 

At a certain temperature, K is 0.040 for the decomposition of two moles of bromine chloride gas (BrCl) to its elements. An equilibrium mixture at this temperature contains bromine and chlorine gases at equal partial pressures of0.0493 atm. What is the equilibrium partial pressure of bromine chloride ... 

The initial pressure of BrCl(g) in a reaction vessel is 1.4 mbar. If the vessel is heated to 500. K, what is the equilibrium composition of the mixture See Table 9.2 for data on the reaction. 

BrCl(g), K = 0.2. Construct a plot of the Gibbs free energy of this system as a function of partial pressure of BrCl as the reaction approaches equilibrium. 

BrCl approaches the normal covalent type still more closely than HI, with a deviation from additivity of less than 1%. The values of A for 6 Linus Pauling and Don M. Yost, Proc. Not. Acad. Sci., 18,414 (1932). 

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