Polyoxymethylene dimethyl ethers (PODEn) are promising diesel additives which can be synthesized from formaldehyde and methanol. In this work, the ternary liquid-liquid equilibria (LLE) were analytically determined at 293.15 K and 313.15 K for the following systems: PODE1 + para-xylene (PX) + water, PODE2 + PX + water, PODE3 + PX + water, PODE4 + PX + water, respectively. The isothermal experimental results have shown a good linear fit in Hand plots and the Othmer-Tobias. The design of the solvent extraction equipment for extracting PODEn from aqueous solution requires an appropriate model for the liquid-liquid phase equilibrium. The well-known NRTL and UNIQUAC thermodynamic models were applied to correlate the experimental data, and the results indicate that the UNIQUAC model gives a better agreement. (C) 2016 Elsevier Ltd.