In this work, the separation of a mixture of dimethyl carbonate (DMC), formaldehyde, and water is studied. In our process, formaldehyde is first extracted using water as the entrainer, and then the azeotrope of DMC–water is separated by extractive distillation with ethylene glycol. To verify the feasibility of the process, the liquid–liquid equilibrium (LLE) data of the DMC–formaldehyde–water system was measured and the vapor–liquid equilibrium (VLE) data of the DMC–ethylene glycol system was also measured at 101.3 kPa. Moreover, the reliability of experimental tie-line data was checked with the Bachman, Hand, and Othmer–Tobias equations, and the thermodynamic consistency of the measured VLE data was verified by the Van Ness test and infinite dilution test. Finally, all the measured values were correlated with the nonrandom two-liquid (NRTL) model and universal quasi-chemical (UNIQUAC) model, and the binary interaction parameters were regressed.

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