Liquid-liquid equilibria (LLE) for N-formylmorpholine + heptane or + decalin and N-formylmorpholine + decane + benzene or + ethylbenzene over a temperature range of 293-338 K were measured. The results were used to estimate the interaction parameters between a new solvent group, NFM (N-formylmorpholine), and the main groups of CH2 (paraffinic CH2), ACH (aromatic CH), ACCH(2) (aromatic CCH2), and CHNA (condensed naphthenic CH) as a function of temperature. The estimated interaction parameters of these groups have been used with other interaction parameters present in the literature to compare calculated values with the experimental LLE equilibrium measurements.