Isobaric vapor–liquid equilibrium for systems containing sulfur compounds

Isobaric vapor–liquid equilibrium (VLE) data for the binary systems of thiophenic compounds with three hydrocarbons in gasoline (2,3-dimethyl-1-butene, 2,3-dimethyl-2-butene and n-heptane) were measured in dilute solutions at 101.33 kPa with a modified Rose–Williams still. General Coulomb meter was used to analyze the compositions of the samples from the vapor–liquid equilibrium systems. The VLE data was compared with the calculated value by the Wilson model with the interaction parameters regressed over the entire concentration range. Results found that neither the activity coefficient model nor the Henryʹs model could describe the VLE behavior of the trace component in the dilute solution accurately. Thus a concept of multi-scale phase equilibrium was proposed.