Kinetic study of the reaction of chlorine atoms with CF3I and the reactions of CF3 radicals with O2, Cl2 and NO at 296 K

✍ Scribed by E. W. Kaiser; T. J. Wallington; M. D. Hurley

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 826 KB
• Volume: 27
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550270302

✦ Synopsis

The kinetics of the gas-phase reaction of C1 atoms with CF31 have been studied relative to the reaction of C1 atoms with CH4 over the temperature range 271-363 K. Using k(C1 + CH4) = 9.6 X exp(-2680/RT) cm3 molecule-' s-', we derive k(C1 + CF3I) = 6.25 X lo-'' exp(-2970/RT) in which E , has units of cal mol-'. CF3 radicals are produced from the reaction of C1 with CF3I in a yield which was indistinguishable from 100%. Other relative rate constant ratios measured at 296 K during these experiments were k(C1 + C2FsI)/k(Cl + CF31) = 11.0 ? 0.6 and k(C1 + C2FsI)/k(Cl + C2H5C1) = 0.49 ? 0.02. The reaction of CF3 radicals with Clz was studied relative to that with 0 2 at pressures from 4 to 700 torr of Nz diluent. By using the published absolute rate constants for K(CF3 + 0 2 ) at 1-10 torr to calibrate the pressure dependence of these relative rate constants, values of the low-and high-pressure limiting rate constants have been determined at 296 K using a Troe expression: ko(CF3 + 0 2 ) = (4.8 ? 1.2) X cm6 molecule-' s-'; K,(CF3 + 0 2 ) = (3.95 ? 0.25) X lo-'' cm3 molecule-' s-'; F, = 0.46. The value of the rate constant k(CF3 + Clz) was determined to be (3.5 ? 0.4) X cm3 molecule-' s-l at 296 K. The reaction of C1 atoms with CF3I is a convenient way to prepare CF3 radicals for laboratory study.