VAPOR-PRESSURES OF FLUOROCARBONS IN POLYOLS, POLYAMINES AND POLYCARBOXYLS

Fluorocarbons which are less damaging to atmospheric ozone levels have recently become available on an industrial scale. It is necessary to assess their solubilities in solvents such as polyols to optimize thei r uses as blowing agents or refrigerants. The equilibrium vapour press ures at 25 degrees C over the refrigerants R22, R124, R142b and R134a in propoxylated polyols, polyamines and polycarboxylates at 19% and 20 % w(F)/w(S) have been measured. The data have been interpreted using t he Flory-Huggins interaction parameter X. This depends quantitatively on the number of basic ether oxygens in the solvent, and on the relati ve acidities of the fluorocarbons as well as the propoxylation precurs or. The vapour pressures over ternary mixtures have been modelled usin g a linear combination of binary chi values corrected by a single adju stable constant independent of the solvent type.