Vapour 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 their uses as blowing agents or refrigerants. The equilibrium vapour pressures at 25 °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 the Flory-Huggins interaction parameter x. This depends quantitatively on the number of basic ether oxygens in the solvent, and on the relative acidities of the fluorocarbons as well as the propoxylation precursor. The vapour pressures over ternary mixtures have been modelled using a linear combination of binary x values corrected by a single adjustable constant independent of the solvent type.