Photofragmentation of a perfluorocarboxylic acid using synchrotron radiation: Study of CF3CF2C(O)OH

DELLA VEDOVA, CARLOS OMAR.; MARTÍNEZ Y. B.; BAVA Y. B.; FILHO R. C.; ROMANO R. M.

sao Paulo

Workshop; 25th RAU; 2015

LNLS/CNPEM

Perfluorinated compounds have been extensively used in industrial applications during thelast years. Recently, some perfluorinated species were detected in tissues of animals, inenvironmental waters, and in the atmosphere.[1,2] Different processes may be responsiblefor the presence of these compounds in the environment. For example, the thermolysis offluoropolymers and the degradation of fluorotelomer alcohols result in the emission ofperfluorocarboxylic species to the atmosphere. In this work, and as part of a general projectaimed to the elucidation of the photofragmentation mechanisms of compounds relevant foratmospheric chemistry, we present the study of perfluoropropionic acid using synchrotronradiation with energies between 7.3 and 300eV. The photoexcitation and photofragmentationof this species was studied in the TGM beamline at LNLS. Above 11.7 eV different ions canbe observed in the PEPICO spectra. At exactly 11.7 eV, COH+, C2F4+, and M+ weredetected. This result shows that the cleavage of two covalent bonds is carried out at energiesbarely higher than the first ionization potential. The peak corresponding to C(O)OH+ wasdetected at 11.8 eV, and CF3CF2+ appeared in the spectra from 15 eV. The parent ion wasonly detected below 16 eV. From that energy, the heaviest ion observed in the PEPICOspectra was the M-OH+ fragment. Unlike the fragments observed in the previously studiedanalogous molecule CF3CF2CF2C(O)Cl,[3] CF+, CF2+, and CF3+ ions were not the mostabundant peaks in the spectra.