Isothermal vapor-liquid equilibrium (VLE) for thiophene + 2,2,4-trimethylpentane were measured at 343.15 and 353.15 K and thiophene + 2-ethoxy-2-methylpropane were measured at 333.15 and 343.15 K with a circulation still. Maximum pressure azeotropes were found in thiophene + 2,2,4-trimethylpentane systems, whereas thiophene + 2-ethoxy-2-methylpropane systems exhibit slight positive deviation from ideality. No azeotropic behavior was found in thiophene+2-ethoxy-2-methylpropane systems. The experimental results were correlated with the Wilson model and also compared with the original UNIFAC, UNIFAC-Dortmund, and the COSMO-RS predictive models. Analyses of liquid and vapor phase composition were determined with gas chromatography. All VLE measurements passed the used thermodynamic consistency tests (integral, infinite dilution and point test). (c) 2007 Elsevier B.V. All rights reserved.