Bromine, reaction with

Little work has been carried out on the gas-phase reaction of bromine with nitric oxide 

Krauss investigated the process using manometric techniques and found kill = 10 - exp(-l,600/Rr)I moIe- .sec  

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Bromine, like chlorine, also undergoes a photochemical chain reaction with hydrogen. The reaction with bromine, however, evolves less energy and is not explosive. 

Bromine. Slip the glass cover of a jar momentarily aside, add 2-3 ml. of bromine water, replace the cover and shake the contents of the jar vigorously. Note that the bromine is absorbed only very slowly, in marked contrast to the rapid absorption by ethylene. This slow reaction with bromine water is also in marked contrast to the action of chlorine water, which unites with acetylene with explosive violence. (Therefore do not attempt this test with chlorine or chlorine water.)... 

Similarly, the reaction with bromine yields the corresponding 5-bromo derivatives, which are suitable substrates for nucleophilic displacement or dehydrohalogenation reactions. Typical nucleophiles (Nu) are H2O, NH, RNH2, and sodium barbiturates ... 

Photochlorination of tetrachloroethylene, observed by Faraday, yields hexachloroethane [67-72-1]. Reaction with aluminum bromide at 100°C forms a mixture of bromotrichloroethane and dibromodichloroethane [75-81-0] (6). Reaction with bromine results in an equiUbrium mixture of tetrabromoethylene [79-28-7] and tetrachloroethylene. Tetrachloroethylene reacts with a mixture of hydrogen fluoride and chlorine at 225—400°C in the presence of zirconium fluoride catalyst to yield l,2,2-trichloro-l,l,2-trifluoroethane [76-13-1] (CFG 113) (7). 

The olefin of the Voc group is very susceptible to electrophilic reagents and thus is readily cleaved by reaction with bromine or mercuric acetate. 

Cyclopropanes undergo a ready reaction with bromine to give 1,3-dibromopropane, and can in turn be formed from 1,3-dibromopropane by the Wurtz reaction. A variation... 

It yields a characteristic reaction with bromine. If a few drops are, dissolved in 3 c.c. of glacial acetic acid and a little bromine vapour allowed to pass down the tube, a fine crimson colour forms which rapidly extends to the whole of the liquid and soon changes to violet and then to indigo blue with phosphoric acid, the acetic acid solution gives a rose madder colour at the junction of the liquids, and when the liquids are mixed, the colour changes to crimson and then slowly to violet. Baker and Smith consider that the sesquiterpene contains one double linkage. Semmler considers that it is a mixture of at least two bodies, one a bicyclic and the other a tricyclic sesquiterpene. 

Myristicin and isomyristicin are distinguished by their reactions with bromine. Myristicin, when treated with two atoms of bromine, yields an oily liquid, whilst isomyristicin yields a crystalline body melting at 109°. If the isomers are dissolved in acetic acid, and treated with bromine until no more is absorbed, the mixture being kept cold all the time, the following compounds are obtained —... 

Electronegative groups do not invariably prevent nuclear bromination, but reaction conditions must be much more severe, and the orientation of substitution may be affected by the substituent. Thus 6-nitroquinoline was brominated in sulfuric acid at 100°C to give the 8-bromo product (71) in 51% yield 8-methyl-5-nitroquinoline gave a 69% yield of the 7-bromo derivative (72) under similar conditions, whereas 7-chloroquinoline was transformed into the 5-bromo product (93%) (88CHE892) (Scheme 35). In a sealed tube reaction with bromine, 8-nitroquinoline gave a mixture... 

Kinetic studies of molecular bromination have been carried out using a variety of solvents other than acetic acid. The bromination of 2-nitroanisole by bromine in water revealed that molecular bromine is the reactive species and that the tribromide ion is very unreactive191. By making allowance for the concentration of free bromine (which differs from the stoichiometric concentration through reaction with bromine ion), good second-order rate coefficients were obtained by application of equation (133) with k2 = 0.062 at 25 °C the dominance of the bimolecular mechanism is to be expected here in view of the trend observed on making acetic acid media more aqueous. 

Furan, reaction with bromine and methanol to yield 2,5-dimethoxy-2,5-dihydrofuran, 40, 29 Fuean, 2,5-DmYDRO-2,5-dim-ethoxy-, 40, 29... 

The reaction with bromine is very rapid and is easily carried out at room temperature, although the reaction is reversible under some conditions. In the case of bromine, an alkene-Br2 complex has been detected in at least one case. Bromine is often used as a test, qualitative or quantitative, for unsaturation. The vast majority of double bonds can be successfully brominated. Even when aldehyde, ketone, amine, so on functions are present in the molecule, they do not interfere, since the reaction with double bonds is faster. 

Acetylene compounds Dicobaltoctacarbonyl Formation of colored complexes. After the reagent excess has been washed out, reaction with bromine vapor yields cobalt bromide, which reacts with a-nitroso-P-naphthol to yield red chromatogram zones on an almost colorless background. [11]... 

Cyanide and thiocyanate anions in aqueous solution can be determined as cyanogen bromide after reaction with bromine [686]. The thiocyanate anion can be quantitatively determined in the presence of cyanide by adding an excess of formaldehyde solution to the sample, which converts the cyanide ion to the unreactive cyanohydrin. The detection limits for the cyanide and thiocyanate anions were less than 0.01 ppm with an electron-capture detector. Iodine in acid solution reacts with acetone to form monoiodoacetone, which can be detected at high sensitivity with an electron-capture detector [687]. The reaction is specific for iodine, iodide being determined after oxidation with iodate. The nitrate anion can be determined in aqueous solution after conversion to nitrobenzene by reaction with benzene in the presence of sulfuric acid [688,689]. The detection limit for the nitrate anion was less than 0.1 ppm. The nitrite anion can be determined after oxidation to nitrate with potassium permanganate. Nitrite can be determined directly by alkylation with an alkaline solution of pentafluorobenzyl bromide [690]. The yield of derivative was about 80t.with a detection limit of 0.46 ng in 0.1 ml of aqueous sample. Pentafluorobenzyl p-toluenesulfonate has been used to derivatize carboxylate and phenolate anions and to simultaneously derivatize bromide, iodide, cyanide, thiocyanate, nitrite, nitrate and sulfide in a two-phase system using tetrapentylammonium cWoride as a phase transfer catalyst [691]. Detection limits wer Hi the ppm range. 

Figure 9 shows the electronic absorption spectrum of a PTTB film which has undergone extensive but incomplete reaction with bromine in a non-in-situ experiment. The absorption spectrum is that expected for a one-dimensional conjugated polymer. The sharpest absorption edge is at about 1490 nm (o.83 eV) and the absorption maximum is located at 1240 nm (1.0 eV). Thus, this material has a bandgap of about 0.83 eV. Note that two small... 

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