Bromine release

However, a complication arose because in the liquid phase bromine, released on fluorination, only equilibrated slowly with the bromine trifluoride. The vapor-phase equilibration Br2 + BrF3 3BrF surprisingly occurs within minutes at 25°C (219). Hence BrF3 was first equilibrated with an excess of Br2. Then the heat of addition of further Br2 was small and reached equilibrium within 5 min provided the BrF3/Br2 mole ratio was held within limits of 7 to 6.5. These mixtures have additional advantages in that the BrF content, which is reported... 

Thin-Layer Chromatography. Thin-layer chromatography was used for many of the compounds which are of interest for either qualitative or quantative analysis. These techniques were used primarily as screening methods to supplement other analytical methods. For some brominated compounds such as TRIS, the detection system reported by Hahn (9) was applicable. This method is based upon the reaction of fluorescein with elemental bromine released through peroxide oxidation. An evaluation in our laboratory of this detection system indicated that semi-quantitative results... 

Hirokawa, J., K. Onaka, Y. Kajii, and H. Akimoto, Heterogeneous Processes Involving Sodium Halide Particles and Ozone Molecular Bromine Release in the Marine Boundary Layer in the Absence of Nitrogen Oxides, Geophys. Res. Lett., 25, 2449-2452 (1998). 

The elemental bromine released during the accumulation stage is sorbed by the active carbon in the anodic space. Magnesium hydroxide is released and sorbed in the cathodic chamber. Further regeneration leads to the cathodic reduction of the sorbed elemental bromine and formation of magnesium bromide. 

Michalowski et al. (2000) calculated that the source of bromine from Br2 photolysis is about an order of magnitude larger than bromine release from BrCl after sunrise. Following BrO formation from the reaction of Br with O3 and HOBr formation by HO2 -b BrO HOBr -b O2 (namely, (4)), further reactions of HOBr with Cl and Br would give rise to enhanced levels of Br2 and BrCl. They also found that heterogeneous halogen chemistry within the snowpack was necessary for the O3 depletion events to occur and that the mass transfer of HOBr to the snowpack is a rate-limiting step. 

Hirokawa J., Onaka K., Kajii Y., and AMmoto H. (1998) Heterogeneous processes involving sodium halide particles and ozone molecular bromine release in the marine boundary layer in the absence of nitrogen oxides. Geophys. Res. Lett. 25, 2449-2452. 

Many methods for sulphide and H2S are based on the reducing properties of S(-II). Hydrogen sulphide reduces molybdate in acid medium to molybdenum blue, and the molybdophosphate to phosphomolybdenum blue [52]. Iron(III) reduced by H2S in the presence of 1,10-phenanthroline gives the orange Fe(phen)3 complex [2,53], Hydrogen sulphide may be determined after conversion into thiocyanate by the reaction with Fe(III) [54]. Sulphide has been determined also by a colour redox reaction with nitroprusside [55-57], In another sensitive reaction the sulphide ions decompose the Ag complex with Cadion 2B and Triton X-100 (e = 2.5-10 ) [58], In another indirect method sulphide releases the chloranilate ion from the Hg(Il) chloranilate [59]. Sulphide has also been determined by a method based on its reaction with bromate, followed by bromination of 2 ,7 -dichlorofluorescein by the bromine released [60]. 

The redox reaction between aluminum and bromine releases heat and creates a cloud of vaporized bromine as some of the liquid bromine boils away. 

Mountain (Spitsbergen Island, Norway), and Greenland Summit in April 2001 (Toyota et al. 2011). As shown in the figure, the O3 depletion does not appear in RUN 1 in which the release of Br is not considered, the episodic O3 depletions are reproduced well by RUN 4 in which Tc is set at —15 °C. From this model investigation, as for the cause for the sporadic bromine explosion, meteorological conditions is suggested to influence the contact time of O3 with sea salt on snow cover by transport and turbulent diffusion. As for the bromine release, the first year fresh snow is thought to be important and it is sensitive to the critical temperature mentioned above. 

This reaction has been discussed as potentially important for bromine cycling on sulphate aerosol [22] and for autocatalytic bromine release from sea-salt aerosol [19,23]. Because of the large [CF]/[Br ] ratio in sea water, the forward reaction (1) is much more important than forward reaction (2). Although the hydrolysis reaction (-1) is faster than reaction (-2), this is of lesser significance because a substantial fraction of the BrCl will react with Br leading to autocatalytic Br activation ... 

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