1691-90-3Relevant articles and documents
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.
