Isobaric vapor–liquid equilibrium for binary system of 2-ethylthiophene + n-octane at 101.33 kPa

• Isobaric vapor–liquid equilibrium for binary system of 2-ethylthiophene + n-octane was measured with a circular still.
• The binary system exhibited positive deviation from ideal system and no azeotropic behavior was found.
• The experimental data were correlated with the Wilson, NRTL and UNIQUAC models.
• All VLE measurement passed the thermodynamic consistency test.

Isobaric vapor–liquid equilibrium (VLE) data of 2-ethylthiophene and n-octane binary system were measured at 101.33 kPa with a modified Rose-Williams still. Gas chromatography was used to analyze compositions of the samples from the vapor–liquid equilibrium system. The VLE measurement passed the thermodynamic consistency test proposed by Herington and no azeotropic behavior was found. The experimental data were correlated by Wilson, the non-random two-liquid (NRTL) and universal quasi-chemical activity coefficient (UNIQUAC) models, respectively. The corresponding parameters for the three models were obtained. Results showed that the Wilson model gave better predictions than NRTL and UNIQUAC models.