Atmospheric lifetimes and global warming potentials of hydrofluoroethers: Reactivity toward OH, UV spectra, and IR absorption cross sections
The rate constants for the reactions of OH radicals with the fluorinated ethers, CHF{sub 2}-O-CHF{sub 2} (HFOC-134) and CF{sub 3}CH{sub 2}-O-CH{sub 2}CF{sub 3} (HFOC-356mff), were measured using the flash photolysis resonance fluorescence technique over the temperature range 277--370 K to give the following Arrhenius expressions: k{sub HFOC-356mff}(T) = (2.32{sub {minus}0.41}{sup +0.46}) x 10{sup {minus}12} exp{l{underscore}brace}{minus}(790 {+-} 47)/T{r{underscore}brace} cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}. On the basis of the analysis of the available experimental results, the following Arrhenius expression can be recommended for the rate constant of the reaction between OH and HFOC-134: k{sub HFOC-134}(T) = (0.82{sub {minus}0.24}{sup +0.34}) x 10{sup {minus}12} exp{l{underscore}brace}{minus}(1,730 {+-} 110)/T{r{underscore}brace} cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}. Atmospheric lifetimes were estimated to be 24.8 years for HFOC-134 (23.8 years based on the results of this study alone) and 0.3 years for HFOC-356mff. Infrared absorption cross sections of HFOC-134, HFOC-356mff, and HFOC-125 (CHF{sub 2}-O-CF{sub 3}) were measured at T = 295 K from 500 to 1,600 cm{sup {minus}1} and the global warming potentials of the three compounds were estimated. Ultraviolet absorption spectra of the ethers were measured between 160 and 220 nm. The general pattern of reactivity of hydrofluoroethers toward OH is discussed.
- Research Organization:
- National Inst. of Standards and Technology, Gaithersburg, MD (US)
- OSTI ID:
- 20013058
- Journal Information:
- Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Vol. 103, Issue 48; Other Information: PBD: 2 Dec 1999; ISSN 1089-5639
- Country of Publication:
- United States
- Language:
- English
Similar Records
Potential chlorofluorocarbon replacements: OH reaction rate constants between 250 and 315 K and infrared absorption spectra
Kinetics and thermochemistry of the OH radical reaction with CF{sub 3}CCl{sub 2}H and CF{sub 3}CFClH