Equilibrium, Kinetic, and UV-Spectral Characteristics of Aqueous Bromine Chloride, Bromine, and Chlorine Species

Abstract

Bromine chloride in the presence of chloride ion forms the dichlorobromate(1) ion, BrClz-, where K1 = [BrClz-]/ ([BrCl(aq)][Cl-1) = 6.0 M-I. Equilibrium constants (all at 25.0 "C, p = 1.00 M) are also determined for KZ = [Br2Cl-]/([BrCl(aq)][Br-]) = 1.8 x lo4 M-', for K3 = [Br2Cl-]/([Brz(aq)][Cl-]) = 1.3 M-' and for K4 = [Br3-]/ [Brz(aq)][Br-] = 16.1 M-'. UV absorption bands are resolved for BrC12-at 232 nm ( E 32 700 M-l cm-') and 343 nm ( E 312 M-' cm-'), for BrzC1-at 245 nm ( E 24 900 M-' cm-') and 381 nm (6 288 M-' cm-l), and for Br3-at 266 nm ( E 40 900 M-' cm-l). The W spectral properties of Clz(aq), CIS-, Brz(aq), and Br-are examined and compared. The reaction between Cl~(aq) and Br-to form BrC12-occurs at the diffusion-controlled limit; the rate constant, (7.7 f 1.3) x lo9 M-' s-', is measured by the pulsed-accelerated-flow method. The rapid formation of BrClz-can be used as an analytical method for trace bromide ion, where as little as mol % Br-can be detected in aqueous solutions of HCl or chloride salts.

Bromine activation in the troposphere by the dark reaction of O3 with seawater ice

“…The equilibria and reaction kinetics of BrCl in aqueous solutions at 298 K and an ionic strength of 1.0 M have been reported by Margerum and coworkers (Wang et al, 1994). In aqueous solution, BrCl rapidly hydrolyzes (k > 105 s -1) to form HOBr.…”

“…CI 2 was not detected here upon irradiation, which may reflect slower reactions in ice and at the lower temperature of these experiments. In addition, if small amounts of CI 2 were generated in the ice surface layer, the fast reaction with Br-in the bulk (Wang et al, 1994) and at the interface (Hu et al, 1995) would form BrCl 2-which is in equilibrium with BrCl and CI-. Reaction at the interface in particular could lead to the very small amounts of gaseous BrCl observed upon irradiation.…”

Production of Brominating Intermediates by Myeloperoxidase

“…Based on the chemistry of the interhalogen compounds (40,41), we propose that BrCl is were performed as described in the legend to Fig. 3.…”

Bromide Tolerance in Plants: A Case Study on Halophytes of Indian Coast

“…Estimation of Br − ion seems to be more difficult, but an interesting problem [19,[21][22][23][24][25][26][27][28][29]. Earlier methods based on Spectrophotometry consisted of transformation of Br − to Br 3 − via BrO 3 − by employing hypochlorite solution [24] or the oxidation of Br − with chloramines-T and the subsequent bromination of phenol red [25] which had serious limitations like incongruity observed on the molar absorptivities of Br 3 − at 267 nm [25][26][27][28], involvement of carcinogenic materials [29], or dependence of accuracy and precision of results on reaction time [30]. Very recently, an easy and reliable spectrophotometric method had been developed to enable the determination of bromide ion in 0.1% KBrO 3 -4% H 2 SO 4 medium in the presence of high chloride ion concentrations [19].…”