Trifluoroacetic acid production from trifluoroacetyl peroxynitrate degradation in the presence of water

The possibility of formation of trifluoroacetic acid (TFA) from the gas phase reaction of trifluoroacetyl peroxynitrate (FPAN) with water was investigated using a large photochemical chamber and FTIR spectroscopy. After 298 hours of exposure of FPAN to 180 mTorr water approximately 31% of FPAN had decayed away. The formed TFA constituted (15±1)% of the consumed FPAN. As a control experiment, FPAN was left in the chamber without water present and the results indicated some TFA production. Assuming that the formation of TFA formation in our experiments is due only to the gas phase reaction CF 3 C(O)O 2 NO 2 + H 2 O → CF 3 C(O)OH + HOONO 2 , the observed decay rate of FPAN indicates an upper limit for the rate coefficient for the reaction of 3.3 x 10 -23 cm 3 molecule -1 s -1 . In the atmosphere formation of TFA from the gaseous reaction of FPAN with water is expected to be of little importance relative to known sources of TFA. • TFA can be formed in the atmospheric reaction of FPAN with gas phase water • Formation of TFA from the reaction of FPAN with water is of little importance • The rate coefficient for the title reaction is less than 3.3x10 -23 cm 3 molecule -1 s -1