<b>The Kinetics of Halogen Hydrolysis</b>

Eigen, Manfred; Kustin, Kenneth

doi:10.1021/ja00867a005

Cited by 361 publications

(264 citation statements)

References 2 publications

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“…Therefore, the uptake coefficient, γ upt , becomes 0.55, which already indicates that uptake might have been accommodation limited. Whether the resistance to reaction in the liquid phase limited the uptake is mainly determined by the first order loss rate in the liquid phase due to the equilibrium reaction (1), with forward and reverse rate constants 1.6 × 10 10 M −2 s −1 and 110 s −1 , respectively (Eigen and Kustin, 1962). The major uncertainty with assessing this rate is the H + concentration in the deliquescent particles under our experimental conditions.…”

Section: Resultsmentioning

confidence: 95%

“…The bulk liquid phase chemistry of reaction (1) has been explored by Eigen and Kustin (1962), and with respect to its significance to the marine boundary layer, Fickert et al (1999) investigated the Br 2 and BrCl yield in the gas-phase for mixed bromide and chloride solutions as a function of pH. This chemistry is not restricted to the Arctic boundary layer.…”

Section: Introductionmentioning

confidence: 99%

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Accommodation coefficient of HOBr on deliquescent sodium bromide aerosol particles

et al. 2002

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Abstract. Uptake of HOBr on sea salt aerosol, sea salt brine or ice is believed to be a key process providing a source of photolabile bromine (Br 2 ) and sustaining ozone depletion cycles in the Arctic troposphere. In the present study, uptake of HOBr on sodium bromide (NaBr) aerosol particles was investigated at an extremely low HOBr concentration of 300 cm −3 using the short-lived radioactive isotopes 83−86 Br. Under these conditions, at maximum one HOBr molecule was taken up per particle. The rate of uptake was clearly limited by the mass accommodation coefficient, which was calculated to be 0.6±0.2. This value is a factor of 10 larger than estimates used in earlier models. The atmospheric implications are discussed using the box model "MOCCA", showing that the increase of the accommodation coefficient of HOBr by a factor of 10 only slightly affects net ozone loss, but significantly increases chlorine release.

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Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Accommodation coefficient of HOBr on deliquescent sodium bromide aerosol particles

et al. 2002

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“…The output of the trap was monitored by the CIMS and effectively all Br 2 was found to be scrubbed by the solution, consistent with efficient detection of Br 2 by the MC. Br 2 can be hydrolyzed to form Br − and HOBr in aqueous solution, with a hydrolysis rate constant, k 19 , of 110 s −1 (at 20 • C) (Eigen and Kustin, 1962). This suggests that each Br 2 molecule produces one bromide ion which is detected with near 100 % efficiency by the MC.…”

Section: Brmentioning

confidence: 99%

Characterization of soluble bromide measurements and a case study of BrO observations during ARCTAS

et al. 2012

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Abstract.A focus of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARC-TAS) mission was examination of bromine photochemistry in the spring time high latitude troposphere based on aircraft and satellite measurements of bromine oxide (BrO) and related species. The NASA DC-8 aircraft utilized a chemical ionization mass spectrometer (CIMS) to measure BrO and a mist chamber (MC) to measure soluble bromide. We have determined that the MC detection efficiency to molecular bromine (Br 2 ), hypobromous acid (HOBr), bromine oxide (BrO), and hydrogen bromide (HBr) as soluble bromide (Br − ) was 0.9±0.1, 1.06+0.30/−0.35, 0.4±0.1, and 0.95±0.1, respectively. These efficiency factors were used to estimate soluble bromide levels along the DC-8 flight track of 17 April 2008 from photochemical calculations constrained to in situ BrO measured by CIMS. During this flight, the highest levels of soluble bromide and BrO were observed and atmospheric conditions were ideal for the spaceborne observation of BrO. The good agreement (R 2 = 0.76; slope = 0.95; intercept = −3.4 pmol mol −1 ) between modeled and observed soluble bromide, when BrO was above detection limit (>2 pmol mol −1 ) under unpolluted conditions (NO<10 pmol mol −1 ), indicates that the CIMS BrO measurements were consistent with the MC soluble bromide and that a well characterized MC can be used to derive mixing ratios of some reactive bromine compounds. Tropospheric BrO vertical column densities (BrO VCD ) derived from CIMS BrO observations compare well with BrO VCD TROP from OMI on 17 April 2008.

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“…Oxidation of condensed phase bromides or HBr to gas phase bromine could solve this inconsistency (McConnell et al, 1992;Tang and McConnell, 1996). Finlayson-Pitts et al (1990) proposed the surface oxidation of Br À by dinitrogenpentoxide, while Fan and Jacob (1992) propagated the heterogeneous oxidation of HBr by hypobromous acid, HOBr (Eigen and Kustin, 1962), on ice or aerosol surfaces see Eq. (13).…”

Section: Oclo Hm 3 O Clo 12mentioning

confidence: 99%

The role of bromine and chlorine chemistry for arctic ozone depletion events in Ny-Ålesund and comparison with model calculations

1999

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Abstract. During the Arctic Tropospheric Ozone Chemistry (ARCTOC) campaigns at Ny-A Ê lesund, Spitsbergen, the role of halogens in the depletion of boundary layer ozone was investigated. In spring 1995 and 1996 up to 30 ppt bromine monoxide were found whenever ozone decreased from normal levels of about 40 ppb. Those main trace gases and others were speci®cally followed in the UV-VIS spectral region by dierential optical absorption spectroscopy (DOAS) along light paths running between 20 and 475 m a.s.l.. The daily variation of peroxy radicals closely followed the ozone photolysis rate J(O 3 (O 1 D)) in the absence of ozone depletion most of the time. However, during low ozone events this close correlation was no longer found because the measurement of radicals by chemical ampli®cation (CA) turned out to be sensitive to peroxy radicals and ClO x . Large CA signals at night can sometimes de®nitely be assigned to ClO x and reached up to 2 ppt. Total bromine and iodine were both stripped quantitatively from air by active charcoal traps and measured after neutron activation of the samples. Total bromine increased from background levels of about 15 ppt to a maximum of 90 ppt during an event of complete ozone depletion. For the spring season a strong source of bromine is identi®ed in the pack ice region according to back trajectories. Though biogenic emission sources cannot be completely ruled out, a primary activation of halogenides by various oxidants seems to initiate an ecient autocatalytic process, mainly driven by ozone and light, on ice and perhaps on aerosols. Halogenides residing on pack ice surfaces are continuously oxidised by hypohalogenous acids releasing bromine and chlorine into the air. During transport and especially above open water this air mixes with upper layer pristine air. As large quantities of bromine, often in the form of BrO, have been observed at polar sunrise also around Antarctica, its release seems to be a natural phenomenon. The source strength of bromine from halogen activation on the pack ice, as based on the measured inorganic bromine levels, averages about 1012 Br-atoms m À2 s À1 during sunlit periods in Arctic spring. The total source strength of inorganic bromine from sunlit polar regions may therefore amount to 30 kt y À1 .

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The Kinetics of Halogen Hydrolysis

Cited by 361 publications

References 2 publications

Accommodation coefficient of HOBr on deliquescent sodium bromide aerosol particles

Accommodation coefficient of HOBr on deliquescent sodium bromide aerosol particles

Characterization of soluble bromide measurements and a case study of BrO observations during ARCTAS

The role of bromine and chlorine chemistry for arctic ozone depletion events in Ny-Ålesund and comparison with model calculations

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