Hydrochlorofluorocarbons global warming potentials

One technical approach to solve this environmental problem is to eliminate the chlorine content of CFCs, primarily by replacing any chlorine atoms with fluorine atoms in these molecules. Hydrochlorofluorocarbons (HCFC s) do not have inqtact zero on the ozone layer and although they have been used in this period, they are already currently subject to restrictions and will be proscribed fi-om 2025. Hydrofluorocarbons (HFC s) have ODP (Ozone Depletion Potential) equal to zero and low GWP (Global Warming Potential) and they are therefore designated as substitutes to CFCs in the field of refijgeration [3]. 

FIGURE 54.8 Ozone-depleting potential and global warming potential of chlorofluorocarbons (CFC) and hydrochlorofluorocarbons (HCFC) relative to Rll = 1. 

Vertrel KCD-9547 is a proprietary azeotrope-like blend of Vertrel XF hydrofluorocarbon with trans-1,2-dichioro-ethylene and cyclopentane. It is ideally suited for use in vapor degreasing equipment to remove light oils, fingerprints, and particulate contaminants. Vertrel KCD-9547 is specially formulated to provide a high degree of compatibility with plastics, elastomers, and other nonferrous metals, such eis in aerospace parts. Vertrel KCD-9547 is nonflammable, has "zero" ozone depletion potential, and heis low global warming potential. It can replace CFC-113,1,1,1 -trichloroethane (1,1,1 -TCA), hydrochlorofluorocarbons (HCFC), and perfluorocarbons (RFC) in many applications. 

In order to enable the fast discontinuation of the production and use of fully halogenated CFCs, hydro-chlorofluorocarbons were introduced in industry as a transition stage. The atmospheric fate and impact of these hydrochlorofluorocarbons and chlorinated solvents are described in [387]. The authors come to the conclusion, that these compounds, with the exception of 1,1,1-trichIoroethane, make a small or insignificant contribution to the stratospheric ozone depletion, global warming, photochemical smog , acid rain or chloride and fluoride levels in precipitations. The ozone depletion potentials are 10 to 50 times lower than that of CFCll or CFC12, mainly as a consequence of their shorter atmospheric lifetime—some months to 10 years—due to destruction in the atmosphere. 

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