FT-IR Study of the Kinetics and Products of the Reactions of Dimethylsulphide, Dimethylsulphoxide and Dimethylsulphone with Br and BrO

Authors: Ballesteros B.¹; Jensen N.R.²; Hjorth J.²

Source: Journal of Atmospheric Chemistry, Volume 43, Number 2, October 2002 , pp. 135-150(16)

Publisher: Springer

Abstract:

Kinetics and products of the gas-phase reactions of dimethylsulphide (DMS), dimethylsulphoxide (DMSO) and dimethylsulphone (DMSO₂) with Br atoms and BrO radicals in air have been investigated using on-line Fourier Transform Infrared Spectroscopy (FT-IR) as analytical technique at 740 ± 5 Torr total pressure and at 296 ± 3 K in a 480 L reaction chamber. Using a relative rate method for determining the rate constants; the following values (expressed in cm³molecule^-1 s^-1) were found: k_DMS+Br = (4.9 ±1.0) ×10^-14, k_DMSO + Br < 6 × 10^-14, k_DMSO2 + Br 1 × 10^-15, k_DMSO + BrO = (1.0 ± 0.3) × 10^-14 and k_DMSO2 + BrO 3 × 10^-15 (all values are given with one on the experimental data). DMSO, SO₂, COS, CH₃SBr and CH₃SO₂Br were identified as the main sulphur containing products of the oxidation of DMS by Br atoms. From the reaction between DMSO and Br atoms, DMSO₂and CH₃SO₂Br were the only sulphur containing products that were identified. DMSO, DMSO₂ and SO₂ were identified as the main sulphur containing products of the reaction between DMS and BrO. DMSO₂ was found to be the only product of the reaction between DMSO and BrO. For the reactions of DMSO₂ with Br and BrO no products were identified because the reactions were too slow. The implications of these results for atmospheric chemistry are discussed.

Keywords: bromine atom; bromide oxide; DMS; DMSO; DMSO₂; kinetics; products

Language: English

Document Type: Research article

Affiliations: 1: Universidad de Castilla – La Mancha, Departamento de Química Física, Facultad de Ciencias Química, Campus Universitario s/n, E-13071 Ciudad Real, Spain 2: European Commission, Joint Research Centre, Environment Institute, TP 272, I-21020 Ispra (VA), Italy

Publication date: 2002-10-01

• In this: publication
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• In this Subject: Meteorology & Climatology
• By this author: Ballesteros B. ;  Jensen N.R. ;  Hjorth J.

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