Photochemical degradation of 2,2,2 trifluoroethyl iodide at 254 nm

MALISA S. CHIAPPERO Y GUSTAVO A. ARGÜELLO

Florianópolis

Congreso; 10th Latin American Conference on Physical Organic Chemistry; 2009

Photochemical degradation of 2,2,2 trifluoroethyl iodide at 254 nm.   Malisa S. Chiappero, and Gustavo A. Argüello.   INFIQC, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba CP 5000, Argentina, e-mail: malisa@fcq.unc.edu.ar   The polyfluorinated iodides have been suggested as possible CFC’s substitutes and are used in polymerization processes, as monomers. In their atmospheric degradation are produced perfluorocarboxylic acids (PFCAs, CxF2x+1C(O)OH). These last have been detected in Artic fauna, water, and ice. The long chain PFCAs are bioaccumulative, resist degradation via oxidation, hydrolysis, or reduction under biotic and abiotic conditions, and appear to be persistent in the environment.  Short carbon chain members (C<6) of iodide are recently suggested as monomer replacement to decrease the presence of bioaccumulative PFCAs in the environment. This is a study of photolytic degradation of CF3CH2I. This molecule present a l max= 261 ± 1 nm with  s= (7.55± 0.6) x10-19 molecule-1 cm2. Irradiation with 254 nm wavelength produces the homolytic rupture of C-I bond. The present work will show the mechanism, the rate constants, the quantum yield and the simulated lifetime of the CF3CH2I. Experiment using excess of NO or O2 were also running in order obtain more information about the photolytic system. UV-vis spectrum of CF3CH2I   [1] 3M Company. Fluorochemical Use, Distribution and Release OVerView; U. S. EPA Administrative Record AR226-0550; U. S. Environmental Protection Agency; U. S. Government Printing Office: Washington, DC, 1999. [2] Roehl, C. M., J. B. Burkholder, G. K. Moortgat, A. R. Ravishankara, and P. J. Crutzen (1997), J. Geophys. Res., 102(D11), 12,819–12,829. [3] K. L. Bierbrauer, M. S. Chiappero, F. E. Malanca y G.  A. Argüello. J. Photochem. and Photobiol. A: Chem.: 122 (1999) 73-78. [4] Chamberlain, G. A.; Whittle, E., Trans. Faraday Soc., 1971, 88. [5] Malisa S. Chiappero, Gustavo A. Argüello, Michael D. Hurley, Timothy J. Wallington, Chemical Physics Letters 461 (2008) 198–202.