The uptake of HO2 radicals on synthetic sea salt, NaCl, NaBr and MgCl(2).6H2O dry solid films was studied over the temperature range 240 to 340 K and at 1 Torr pressure of helium using a discharge flow reactor coupled to a modulated molecular beam mass spectrometer. The Arrhenius expressions (calculated with geometric surface area) were obtained for the uptake coefficient of HO2: 3.1x10(-9) exp[(3990+/-200)/T], 2.2x10(-8) exp[(3340+/-180)/T], 1.2x10(-8) exp[(3570+/-180)/T] and 3.8x10(-5) exp[(1710+/-60)/T] on sea salt, NaCl, NaBr and MgCl(2).6H2O, respectively (quoted uncertainty is 2sigma statistical). H2O2 was observed as a main product of HO2 interaction with salt surface indicating a heterogeneous HO2 self reaction mechanism. The results show that the HO2 loss through heterogeneous interaction with salt surface is not sufficiently rapid to explain the observed differences between modeled and measured HO2 concentrations in remote coastal areas.

Laser flash photolysis combined with competition kinetics with SCN− as the reference substance has been used to determine the rate constants of OH radicals with three fluorinated and three chlorinated ethanols in water as a function of temperature. The following Arrhenius expressions have been obtained for the reactions of OH radicals with (1) 2‐fluoroethanol, k1(T) = (5.7 ± 0.8) × 1011 exp((−2047 ± 1202)/T) M−1 s−1, (2) 2,2‐difluoroethanol, k2(T) = (4.5 ± 0.5) × 109 exp((−855 ± 796)/T) M−1 s−1, (3) 2,2,2‐trifluoroethanol, k3(T) = (2.0 ± 0.1) × 1011 exp((−2400 ± 790)/T) M−1 s−1, (4) 2‐chloroethanol, k4(T) = (3.0 ± 0.2) × 1010 exp((−1067 ± 440)/T) M−1 s−1, (5) 2, 2‐dichloroethanol, k5(T) = (2.1 ± 0.2) × 1010 exp((−1179 ± 517)/T) M−1 s−1, and (6) 2,2,2‐trichloroethanol, k6(T) = (1.6 ± 0.1) × 1010 exp((−1237 ± 550)/T) M−1 s−1. All experiments were carried out at temperatures between 288 and 328 K and at pH = 5.5–6.5. This set of compounds has been chosen for a detailed study because of their possible environmental impact as alternatives to chlorofluorocarbon and hydrogen‐containing chlorofluorocarbon compounds in the case of the fluorinated alcohols and due to the demonstrated toxicity when chlorinated alcohols are considered. The observed rate constants and derived activation energies of the reactions are correlated with the corresponding bond dissociation energy (BDE) and ionization potential (IP), where the BDEs and IPs of the chlorinated ethanols have been calculated using quantum mechanical calculations. The errors stated in this study are statistical errors for a confidence interval of 95%. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 174–188, 2008

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Relative rate method at the temperature of 298 K and pressure of 1013 hPa and GC MS detection were used for the study of kinetics of the reactions of Cl atoms with H 2 C=CCl 2 , cis ClHC=CHCl, trans ClHC=CHCl, ClHC=CCl 2 , and Cl 2 C=CCl 2 . The reaction products were identified by FTIR spectroscopy. A mechanism for the atmospheric degradation of chloro ethenes has been suggested.

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