Being an extraction solvent, N-formylmorpholine (NFM) is widely used to separate aromatic and aliphatic hydrocarbons. In order to get the LLE data and the interaction parameters of the ternary system of (NFM + ethylbenzene + 2,2,4-trimethylpentane), the (liquid + liquid) equilibrium (LLE) data were measured for the ternary system under atmospheric pressure and at temperatures (303.15, 313.15, and 323.15) K in this work. The data can also demonstrate the ability for NFM to remove ethylbenzene from the mixture with 2,2,4-trimethylpentane. The complete phase diagrams were obtained by determining the solubility and the tie-line data. The tie-line compositions were correlated by Othmer-Tobias equation. The correlation factors r(2) are bigger than 0.981. The universal quasi-Chemical activity coefficient (UNIQUAC) and the nonrandom two liquids equation (NRTL) were used to calculate the phase equilibrium data of the system with the interaction parameters fitted from the experimental data. It is found that both UNIQUAC and NRTL models could provide good correlations for the LLE data of the system. The root mean square deviation (RMSD) values for the NRTL and UIQUAC models are less than 0.0083 at all temperatures. In addition, the distribution coefficients, separation factors and selectivity were evaluated for the immiscibility region and the extracting capability of the solvents. (C) 2012 Elsevier B.V. All rights reserved.