Trifluoroacetyl peroxynitrate (CF3C(O)O2NO2, FPAN) degradation in wet atmosphere

Abstract

Trifluoroacetyl peroxynitrate (FPAN) is the fluorinated analogue of PAN, proposed as a degradation intermediate of fluorinated compounds like CFC (chlorofluorocarbons) and their replacements. FPAN presents a longer atmospheric lifetime in comparison with the hydrogenated PAN. On the other hand, participation of water in atmospheric processes have received significant attention due to its potential impact on the stability of pollutants and chemical reactions. For example, the interaction between PAN and water by van der Waals interactions can lead to an increase in the degradation rate of PAN. The present work expands the knowledge about the stability of fluorinated peroxynitrates in wet atmosphere.The interaction between FPAN and water was studied from mixtures containing FPAN/H2O and FPAN/H2O/NO2 and monitored by infrared spectroscopy. The analysis of spectra reveals formation of CF3C(O)OH in both systems. Ab initio calculations were performed to explore the interactions at molecular level.Finally, a reaction mechanism is proposed considering the experimental evidence and theoretical calculations results. Rate coefficients for the formation of CF3C(O)OH were estimated using a kinetic software.