Rate constants and arrhenius parameters for the reactions of Cl atoms with the halogenated ethers:: CF3CH2OCHF2, CF3CHClOCHF2, and CF3CH2OCClF2

Rate constants have been determined for the reactions of Cl atoms with the halogenated ethers CF3CH2OCHF2, CF3CHClOCHF2, and CF3CH2OCClF2 using a relative-rate technique. Chlorine atoms were generated by continuous photolysis of Cl-2 in a mixture containing the ether and CD4. Changes in the concentrations of these two species were measured via changes in their infrared absorption spectra observed with a Fourier transform infrared (FTIR) spectrometer. Relative-rate constants were converted to absolute values using the previously measured rate constants for the reaction. Cl + CD4 --> DCl + CD3. Experiments were carried out at 295, 323, and 363 K, yielding the following Arrhenius expressions for the rate constants within this range of temperature: Cl + CF3CH2OCHF2: k = (5.1(5) +/- 0.7) x 10(-12) exp(-1830 +/- 410 K/T) cm(3) molecule(-1) s(-1) Cl + CF3CHClOCHF2: k = (1.6 +/- 0.2) x 10(-11) exp(-2450 +/- 250 K/T) cm(3) molecule(-1) s(-1) Cl + CF3CH2OCClF2: k = (9.6 +/- 0.4) x 10(-12) exp(-2390 +/- 190 K/T) cm(3) molecule(-1) s(-1) The results are compared with those obtained previously for the reactions of Cl atoms with other halogenated methyl ethyl ethers. (C) 2001 John Wiley & Sons, Inc.