The kinetics of the reactions of chlorine atoms with acrylates have been studied by the relative kinetic method. While there are a few studies in the literature of OH radical reactions with unsaturated esters there are almost no data concerning their Cl-initiated degradation. In this work, we report the rate coefficient for the reactions of Cl with CH2=CHC(O)OCH3, CH2=C(CH3)C(O)OCH3 and CH2=C(CH3)C(O)O(CH2)3CH3.
The experiments were performed in the temperature range of 283-313K and atmospheric pressure in a large volume photoreactor using in situ FTIR analysis to monitor the decay of the organics and the reference compounds.
The kinetic data obtained were used to derive the following Arrhenius expressions (in units of cm3 molecule-1 s-1) : k1 = (0.59 ± 0.11) x 10-11 exp[(1.097 ± 0.098) x 103 / RT], k2 = (3.77 ± 1.12) x 10-11 exp[-(16.68 ± 1.54) x 103 / RT], k3 = (1.34 ± 1.04) x 10-11 exp[-(19.59 ± 3.21)
x 103 / RT]. This is the first temperature dependence study of the three reactions cited above. Negative temperature dependencies of the rate constants were obtained for the three reactions studied in agreement with that an addition to the double bond as the main reaction path like for Cl + alkene and Cl + unsaturated and oxygentated VOCs reactions.
x 103 / RT]. This is the first temperature dependence study of the three reactions cited above. Negative temperature dependencies of the rate constants were obtained for the three reactions studied in agreement with that an addition to the double bond as the main reaction path like for Cl + alkene and Cl + unsaturated and oxygentated VOCs reactions.
Additionally, product identification under atmospheric conditions was performed for the first time for these unsaturated esters. The product distribution suggests that the addition of Cl to the less substituted carbon atom of the double bond is preferred, followed by decomposition of the 1,2-hydroxyalcoxy radicals formed.
