Synthesis of Key CFC Alternatives

A direct one-step route to 1,1,1,2,-tetrafluoroethane (HFC-134a CF3CH2F) can be written as shown in Eq. (6). Currently, no commercially viable process has been described for this approach involving high-conversion single-pass yields. This has to do with equilibrium limitations, as explained below. Because of this, decoupling of the overall process into 

A major drawback associated with chromium oxide-based systems for this chemistry has been one of catalyst life. These deactivate rather rapidly, es- 

An exceptional catalyst for isomerization of CFC-113 to CFC-113a is anhydrous aluminum chloride as reported by Miller (28). This isomerization is usually carried out in the liquid phase and under mild conditions. Some disproportionation of CFC-113a to CFC-114a and CF2CICCI3 (CFC-112a) is also observed on prolonged contact with catalyst. The use of trace quantities of metals such as chromium and manganese is claimed to have a beneficial effect in this process (29). There is an initial activation period 

Replacement of the chlorines in CFC-114a through catalytic hydrogenolysis produces HFC-134a, as shown in Eq. (14). Bitner et al. have studied 

The facile hydrogenolysis of a trichloropentafluoropropane to the corresponding trihydro analog using palladium on carbon has been reported by 

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