Photolysis of 1,1,1‐difluorochloroethane (Freon 142) at 147 nm

Abstract

Abstractl,l,l-l~ifluorochloroethane (Freon 142) was photolyzed a t 147 nm in the pressure range of 3.6-20.6 torr. The effects of added NO, €€& and CF, were investigated. The extinction coefficient a t 147 nm and 296°K was determined to be 64 f 8 atm-' . cm-*.The molecule photodecomposes largely by a,@ elimination of HC1 to give 1,l-difluoroethylene (+ = 0.74 f 0.06). There is no observable elimination of HF, but there is strong evidence for the elimination of the elements of FC1 though the relative importance of this process is minor, as are contributions from carbon-carbon and carbon-halogen bond fission.The 1,l-difluoroethylene formed is undoubtedly vibratonally excited and is the source of a pressure-dependent small yield of fluoroacetylene. Over the pressure range studied there is no evidence that the major primary process itself is affected by changes in total pressure as is the case in the 147-nm photolysis of ethyl chloride.

Photodecomposition of 1,1-difluoro-1,2-dichloroethane at 147 nm

“…In contrast (based on C4 product analysis), little evidence of Cl atom reactions was found in the 147-nm photolyses of CH3CHC12,2 CH3CC13,3 and CF2C1CH3. 4 It is not yet clear whether this difference in the reaction kinetics is solely attributable to structural differences (geometry and degree of halogen substitution). Diagnostically significant in the present system are the competitive abstraction/addition reactions of chlorine atoms.…”

“…2 The production of ozone in the mercury-photosensitized reaction with oxygen has been suggested to take place through an excited Hg02 species.3 More recently, the existence of Hg02 has been questioned as important in the 02-photosensitized reaction, though the data were not sufficiently unequivocal to completely rule out the possibility. 4 In this paper we report the results of some matrix isolation studies which indicate the existence of at least two mercury oxides.…”

Photodissociation and intramolecular dynamics of vibrationally excited CHF2Cl

“…Indeed, they became appealing targets for photodissociation studies, [6][7][8][9][10][11][12][13][14] in particular during the last years, since they were introduced as temporary substitutes for the ozone destroying chlorofluorocarbons ͑CFCs͒. Indeed, they became appealing targets for photodissociation studies, [6][7][8][9][10][11][12][13][14] in particular during the last years, since they were introduced as temporary substitutes for the ozone destroying chlorofluorocarbons ͑CFCs͒.…”