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Heterogeneous interconversion reactions of BrNO2, ClNO2, Br2, and Cl2



Journal of physical chemistry. A 102 (1998), pp.1329-1337
ISSN: 1089-5639
Journal Article
Fraunhofer ITA ( ITEM) ()
bromine compound; chlorine compound

The heterogeneous reactions leading to formation and loss of BrNO2 on salt solutions as a model substrate for atmospheric sea salt aerosol are investigated. Further to the reaction of ClNO2 with bromide solutions, the reaction of Br2 with nitrite solution was found to be a convenient method for the synthesis of BrNO2. We measured the temperaure-dependent lifetime of BrNO2 in a quartz cell and obtained the activation energy EA = 89 +/- 9 kJ/mol for the unimolecular decay at atmospheric pressure. The reactive uptake of BrNO2 and ClNO2 on water and aqueous solutions was determined using a wetted-wall flow tube technique. We observed the reactions Br2+NO2 -> BrNO2+Br-, Cl2+NO2- -> ClNO2+Cl-, and the net reaction ClNO2 + Br- <-> BrNO2+Cl-. BrNO2 and ClNO2 both react with NO2- to release NO2 into the gas phase. Observed concentration profiles in the gas phase and in solution can be described qualitatively by a numerical model of the diffusion and reaction in the experimental setup.