The problem of fluorine compounds interacting with other molecules containing different functional groups is studied. The results of the measurement of infinite dilution activity coefficient data for mixture containing hydrofluoroparaffins and different organics are reported. By using the solution of groups concept (UNIFAC model) it is possible, starting from these data, to characterize the interactions between the groups containing fluorine and other organic groups. This characterization allows the prediction of thermodynamic behavior even for mixtures for which experimental informations are not available.
