Degradation of a series of fluorinated acrylates and methacrylates initiated by OH radicals at different temperatures

GARCÍA, P. LUGO; RIVELA, C. B.; GIBILISCO, R. G.; SALGADO, S.; WIESEN, P.; TERUEL, M. A.; BLANCO, M. B.

RSC Advances

Royal Society of Chemistry

Año: 2020 vol. 10 p. 4264 - 4273

Rate coefficients for the gas-phase reactions of OH radicals with a series of fluorinated acrylates and methacrylates: 2,2,2-trifluoroethylmethacrylate (k1), 1,1,1,3,3,3-hexafluoroisopropylacrylate (k2),1,1,1,3,3,3-hexafluoroisopropylmethacrylate (k3), and 2,2,2-trifluoroethylacrylate (k4) have been measured for the first time as a function of temperature in the range 290?308 K. The kinetic data obtained were used to derive the following Arrhenius expressions (in units of cm3 per molecule per s): k1 = (2.13 ± 0.68) 10^18 exp[(4745 ± 206)/T], k2 = (8.72 ± 0.68)10^15 exp[(2166 ± 205)/T], k3 = (6.30 ± 0.51)10^17 exp[(3721 ± 153)/T] and k4 = (3.93 ± 0.43)10^16 exp[(3140 ± 129)/T]. The experiments were performed at normal atmospheric pressure in synthetic air using a 1080 L photoreactor and coupledwith FTIR analysis to monitor the decay of the substances of interest and the reference compounds. The obtained negative temperature dependencies are in agreement with a mechanism implying an initial addition of the OH radical to the double bond. Atmospheric implications are discussed with reference to the rate coefficients obtained as a function of the temperature.