1691-89-0Relevant academic research and scientific papers
Rate measurement of the reaction of CF2Cl radicals with O 2
Codnia, Jorge,Azcarate, Maria Laura
, p. 755 - 762 (2006)
We have studied the association reaction of the CF2Cl radicals with O2 in presence of N2. The infrared multiple photon dissociation (IRMPD) technique with a homemade TEA CO2 laser was used for the CF2Cl radical generation and the vibrational chemiluminiscence technique was set up for the study of the reaction kinetics. The time-resolved IR fluorescence of the vibrationally excited CF2O photoproduct was used to measure the disappearance rate of these radicals. A kinetic mechanism is presented to account for the rate of production of CF 2O*. The CF2Cl radical association reaction rate with O2, evidence of a direct channel of photoproduct formation and its reaction rate, and the CF2O* collisional deactivation rate have been obtained.
Time Resolved Studies of Intermediate Products in the Oxidation of HCFC 141b (CFCl2CH3)and HCFC (CF2ClCH3)
Moers,Hoffmann,Malms,Zellner
, p. 540 - 552 (2007/10/03)
The oxiueauve degradation of HCFC 14Sb (CFCl2CH3) and HCFC 142b (CF2C1CH3) in the presence of NO at T = 293 K and p = 50 mbar has been studied using laser pulse initiation combined with cw laser long path absorption/UF for the detection of OH and NO2. The absolute yield and temporal behaviour of these products have been found to be sensitive indicators for the reaction behaviour of the alkoxy radicals CFCl2CH2O and CF2ClCH2O, respectively. The rate coefficients for the reactions of the alkoxy radicals with O2 were determined to be k(CFCl2CH2O + O2-CFCl2CHO + HO2) = (2.0±1.0)× 10-15 cm3/s and k(CF2ClCH2O + O2→CF2CiCHO + HO2) = (2.5±1.5)× 10-15 cm3/s. Upper limits for the rate coefficients for unimolecular decomposition of the alkoxy radicals by C-C-bond fission of k(CFCl2CH2O + M→CFCl2 + CH2O-rM)≤ 1.0×103 s-1 and k(CF2ClCH2O + M→CF2Cl + CH2OJ-M)≤1.5×103s-1 were derived. We conclude from these data that CFCl2CHO and CF2ClCHO will be formed as the dominant primary carbonyl products in the oxidation of HCFC 141 b and 142b throughout the troposphere. Moreover, the rate coefficients for the reactions of the HCFCs with OH radicals at T = 293 K have been measured. The values k(CFCl2CH3 +OH→CFCl2CH2 + H2O) = (4.6 ±0.8)×10-15 cm3/s and k(CF2ClCH3 + OH→CF2ClCH2 + H2O) = (2.6±0.4)× 10-15cm3/s were obtained. VCH Verlagsgesel/schaft mbH, 1996.
