Chlorine initiated oxidation studies of hydrochlorofluorocarbons: Results for HCFC-123 (CF3CHCl2) and HCFC-141b (CFCl2CH3)
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Oxidation reactions of the proposed CFC substitutes HCFC-123 (CF3CHCl2) and HCFC-141b (CFCl2CH3) have been studied in the laboratory using long-path Fourier transform infrared spectroscopy. The air oxidation of the HCFCs was initiated by the photolysis of Cl2 forming Cl atoms that abstract H atoms from the HCFC. CF3C(O)Cl was the only carbon containing compound observed in the infrared spectrum of the products of the HCFC-123/Cl2 irradiations and its yield was approximately one. The product data are consistent with formation of CF3C(O)Cl by Cl elimination of the intermediate halogenated alkoxy radical CF3CCl2O. The Cl-initiated oxidation of HCFC-141b led to the formation of CO and C(O)FCl. The product data are consistent with a 1 : 1 relationship between C(O)FCl formed and HCFC-141b reacted. Product data were compatible with both decomposition by cleavage of the C−C bond of the radical CFCl2CH2O leading to the prompt generation of C(O)FCl and reaction of the radical with O2 forming the two carbon halogenated aldehyde CFCl2CH(O), which in the presence of Cl was likely oxidized to C(O)FCl. An approximate method was developed in which the ratio was extracted from analysis of the time evolution of HCFC-141b, C(O)FCl, and CO. The data suggest that the contributions are comparable.
Key wordsHCFC-123 HCFC-141b oxidation CF3C(O)Cl C(O)FCl
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