Peroxynitrates from Telomerics Aldehydes

HENAO DIANA; MALANCA E. FABIO; ARGÜELLO A. GUSTAVO

Natal

Congreso; 13th IGAC Science Conference and 13th Quadrennial iCACGP Symposium; 2014

13th IGAC Science Conference and 13th Quadrennial iCACGP Symposium

Peroxyacyl nitrates are irritating compounds formed by the oxidation of organic volatile compounds in presence of NO2. They are important in atmospheric chemistry because of their role as a reservoir species of NO2 and radical peroxides. On the other hand, fluoro-hydrogenated alcohols (CxF2x+1CH2CH2OH) are widely used in a range of industrial applications and lead to the formation of fluoro-hydrogenated aldehydes (CxF2x+1CH2CH2OH). These, in turn, could react with OH radicals and subsequently with molecular oxygen and NO2 to form CxF2x+1CH2CH2OONO2.In this study we present an atmospheric mechanism that leads to the formation of fluoro-hydrogenated peroxynitrates from C6F13CH2C(O)H and determine the thermal stability as a function of temperature and pressure of C6F13CH2C(O)H and CF3CH2C(O)H. In order to obtain good quantities, they were synthetized in a glass flask, using black lamps (λ > 330 nm) to initiate the oxidation from chlorine atoms, and further purification peroxynitrates were obtained. Identification of products and kinetics studies were performed using infrared spectroscopy.The rate constant for the thermal decomposition for C6F13CH2C(O)OONO2 (1.2 × 10−4 s−1) is similar to the measured by the most abundant peroxynitrates in the atmosphere (PAN, PPN) having similar structure (1.5 × 10−4 and 1.6 × 10−4 s−1, respectively). On the other hand, the activation energy and pre-exponential factor for CF3CH2C(O)OONO2 at 9.0 and 1000 mbar are the following: 108 ± 2 kJ/mol, 1.5 × 1015 and 114 ± 2 kJ/mol, 2.4 × 1016, respectively. The high stabilities of CxF2x+1CH2C(O)OONO2 (x = 1,6) point out that the peroxynitrates formed with fluoro-hydrogenated aldehydes can act as reservoir species for NO2 and CxF2x+1CH2C(O)OO radicals in the atmosphere.