Kinetics of the gas-phase reactions of CHXCFX (X = H, F) with OH (253–328 K) and NO3 (298 K) radicals and O3 (236–308 K)

✍ Scribed by L. Chen; T. Uchimaru; S. Kutsuna; K. Tokuhashi; A. Sekiya

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 359 KB
• Volume: 42
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.20506

✦ Synopsis

Abstract

Rate constants for the reactions of OH and NO~3~ radicals with CH~2~CHF (k~1~ and k~4~), CH~2~CF~2~ (k~2~ and k~5~), and CHFCF~2~ (k~3~ and k~6~) were determined by means of a relative rate method. The rate constants for OH radical reactions at 253–328 K were k~1~ = (1.20 ± 0.37) × 10^−12^ exp[(410 ± 90)/T], k~2~ = (1.51 ± 0.37) × 10^−12^ exp[(190 ± 70)/T], and k~3~ = (2.53 ± 0.60) × 10^−12^ exp[(340 ± 70)/T] cm^3^ molecule^−1^ s^−1^. The rate constants for NO~3~ radical reactions at 298 K were k~4~ = (1.78 ± 0.12) × 10^−16^ (CH~2~CHF), k~5~ = (1.23 ± 0.02) × 10^−16^ (CH~2~CF~2~), and k~6~ = (1.86 ± 0.09) × 10^−16^ (CHFCF~2~) cm^3^ molecule^−1^ s^−1^. The rate constants for O~3~ reactions with CH~2~CHF (k~7~), CH~2~CF~2~ (k~8~), and CHFCF~2~ (k~9~) were determined by means of an absolute rate method: k~7~ = (1.52 ± 0.22) × 10^−15^ exp[−(2280 ± 40)/T], k~8~ = (4.91 ± 2.30) × 10^−16^ exp[−(3360 ± 130)/T], and k~9~ = (5.70 ± 4.04) × 10^−16^ exp[−(2580 ± 200)/T] cm^3^ molecule^−1^ s^−1^ at 236–308 K. The errors reported are ±2 standard deviations and represent precision only. The tropospheric lifetimes of CH~2~CHF, CH~2~CF~2~, and CHFCF~2~ with respect to reaction with OH radicals, NO~3~ radicals, and O~3~ were calculated to be 2.3, 4.4, and 1.6 days, respectively. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 619–628, 2010