Gas phase kinetics for the ozonolysis of n-butyl methacrylate, ethyl crotonate and vinyl propionate under atmospheric conditions

ELIZABETH GAONA COLMÁN, MARÍA B. BLANCO, IAN BARNES AND MARIANO A. TERUEL

CHEMICAL PHYSICS LETTERS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2013 vol. 579 p. 11 - 15

0009-2614

Rate coefficients for the reactions of ozone with n-butyl methacrylate, ethyl crotonate and vinyl propionate have been determined at 298 ± 1K and atmospheric pressure. The decay of the organics was followed using ?in situ? FTIR spectroscopy and the rate coefficients were determined by the relative rate method with different reference compounds. The following room temperature rate coefficients (in cm3 molecule-1 s-1 units) were obtained: k1(O3+CH2=C(CH3)C(O)OC4H9) = (1.09  0.26) × 10-17, k2(O3+CH3CH=CHC(O)OCH2CH3) = (8.14  1.81) × 10-18 and k3(O3+ CH3CH2C(O)OCH=CH2) = (5.42  1.25) × 10-18. This is the first kinetic study for these reactions at atmospheric pressure. The effect of substituent groups on the overall rate coefficients, i.e. the reactivity of the double bond, is analyzed and a comparison is made with the available literature on the reactions of O3 with other unsaturated compounds. An analysis of the available rates of addition of O3 molecules and OH radicals to the double bond of alkenes and unsaturated and oxygenated volatile organic compounds (VOCs) at 298 K has shown that they can be related by the expression: log kOH = 0.39 log kO3 ? 3.67. In addition, atmospheric lifetimes of n-butyl methacrylate, ethyl crotonate and vinyl propionate with respect to reaction with O3 and the other major oxidants are estimated, compared and their relative atmospheric importance assessed.