Isobaric vapor–liquid equilibrium for four binary systems of thiophene

Isobaric vapor–liquid equilibrium (VLE) data for thiophene with four different FCC gasoline compounds (2,3-dimethyl-2-butene, n-heptane, 2-methylbutane and 2,3-dimethyl-1-butene) were measured at 101.33 kPa with a circulation still. All the four binary systems exhibit positive deviations from ideal solution behavior. Especially, thiophene + n-heptane binary system exhibits maximum pressure homogeneous azeotrope at 356.33 K with the composition 0.8499 for thiophene. All the VLE measurements passed the thermodynamic consistency test. Wilson model was used to correlate the experimental VLE data. The infinite dilution activity coefficients for the systems were also presented. The experimental data of thiophene + 2,3-dimethyl-2-butene and thiophene + 2,3-dimethyl-1-butene were correlated by original UNIFAC and UNIFAC-Dortmund models. The interaction parameters of the binary pair C4H4S functional group and CC functional group for the two models were obtained and they were tested reliable by some literature data.