Hydrofluorocarbons tetrafluoroethane

Hydrofluorocarbon-134a or 1,1,1,2-Tetrafluoroethane (HFC-134a) has been developed as a replacement for fully halogenated chlorofluorocarbons because, compared with chlorofluorocarbons, its residence time in the atmo... 

Substitutes for CFCs are available, but none provide a completely satisfactory alternative. Hydrofluorocarbons (HFCs) are organic compounds that behave like CFCs, but do not harm the ozone layer. For example, 1,1,1,2-tetrafluoroethane and 1,1-difluoroethane are HFCs that can be used to replace CFCs in refrigerators and air conditioners. Unfortunately, HFCs are also greenhouse gases. 

Hydrofluorocarbon 134a (1,1,1,2-tetrafluoroethane) is used as a replacement for Freon 12 (see Problem 4.2) for refrigeration applications. (Why is such a replacement necessary and what is the advantage of HFC-134a from an environmental... 

Franklin, J. (1993) The atmospheric degradation and impact of 1,1,1,2-tetrafluoroethane (hydrofluorocarbon 134a). Chemosphere 27, 1565-1601. 

Hydrofluorocarbons (HFCs), including 1,1,1,2-tetrafluoroethane (HFC-134a), have been developed as alternatives to chlorofluorocarbons (CFCs), which are known to contribute to the breakdown of ozone to oxygen in the stratosphere. HFCs do not contribute to the destruction of stratospheric ozone, but some HFCs have global warming potential. They primarily serve as replacements for CFCs in refrig... 

Tetrafluoroethane is a hydrofluorocarbon (HFC) or hydro-fluoroalkane (HFA) aerosol propellant (contains hydrogen, fluorine, and carbon) as contrasted to a CFC (chlorine, fluorine, and carbon). The lack of chlorine in the molecule and the presence of hydrogen reduces the ozone depletion activity to practically zero. Hence tetrafluoroethane can be considered as an alternative to CFCs in the formulation of metered-dose inhalers (MDIs). It has replaced CFC-12 as a refrigerant since it has essentially the same vapor pressure. Its very low Kauri-butanol value and solubility parameter indicate that it is not a good solvent for the commonly used surfactants for MDIs. Sorbitan trioleate, sorbitan sesquioleate, oleic acid, and soya lecithin show limited solubility in tetrafluoroethane and the amount of surfactant that actually dissolves may not be sufficient to keep a drug readily dispersed. 

Tetrafluoroethane (hydrofluorocarbon-134a or HFC-134a, b.p. -25°C), which was developed as a replacement for the chlorofluorocarbons that were banned because of ozone-depleting effects, is approved in the UK for the production of natural food flavor extracts. It can be applied to optimize the extraction of plant materials and provides an environmental advantage, as well as health and safety benefits [55,56]. 

This paper is intended to outline the properties of the hydrofluorocarbon solvent 1,1,1,2-tetrafluoroethane (R-134a) that make it an attractive proposition for the extraction of natural products and to highlight some of extracts that may be obtained. 

Alternatives to CFCs are available. Currently, hydrochlorofluorocarbons (HCFCs), which are more benign in the stratosphere than CFCs, are being used, but because they still contain chlorine, the HCFCs are considered only a transitional solution. By 2020, it is anticipated that hydrofluorocarbons (MFCs) such as 1,1,1,2-tetrafluoroethane (CF3CH2F), which are less susceptible to photochemical decomposition in the stratosphere, will have replaced HCFCs as propellants, refrigerants, and so on. 

The next step was to introduce hydrofluorocarbons, HFCs, like 1,1,1,2-tetrafluoroethane (HFC-134a). Unlike CFCs, it does not contain any chlorine. 

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