OH Radical Reaction Rate Coefficients, Infrared Spectrum, and Global Warming Potential of (CF3)2CFCH CHF (HFO 1438ezy(E)
Rate coefficients, k(T) for the OH radical (E) (CF3)2CFCH CHF (E) 1,3,4,4,4 pentafluoro 3 (trifluoromethyl) 1 butene, HFO 1438ezy(E) gas phase reaction were measured using pulsed laser photolysis laser induced fluorescence (PLP LIF) between 214 and 380 K and 50 and 450 Torr (He or N2 bath gas) and with a relative rate method at 296 K between 100 and 400 Torr (synthetic air) Over the range of pressures included in this study, no pressure dependence in k(T) was observed. k(296 K) obtained using the two techniques agreed to within ~3% with (3.26 0.26) x 10( 13) cm(3) molecule( 1) s( 1) (2s absolute uncertainty) obtained using the PLP LIF technique. k(T) displayed non Arrhenius behavior that is reproduced by (7.34 0.30) x 10( 19)T(2) exp[(481 10)/T) cm(3) molecule( 1) s( 1) With respect to OH reactive loss, the atmospheric lifetime of HFO 1438ezy(E) is estimated to be ~36 days and HFO 1438ezy(E) is considered a very short lived substance (VSLS) (the actual lifetime will depend on the time and location of the HFO 1438ezy(E) emission) On the basis of the HFO 1438ezy(E) infrared absorption spectrum measured in this work and its estimated lifetime, a radiative efficiency of 0.306 W m( 2) ppb( 1) (well mixed gas) was calculated and its 100 year time horizon global warming potential, GWP100, was estimated to be 8.6. CF3CFO, HC(O)F, and CF2O were identified using infrared spectroscopy as stable end products in the oxidation of HFO 1438ezy(E) in the presence of O2. Two additional fluorinated products were observed and theoretical calculations of the infrared spectra of likely degradation products are presented. The photochemical ozone creation potential of HFO 1438ezy(E) was estimated to be ~2.15.
The journal of physical chemistry. A