Experimental isothermal P-x data at T = 313.15 K for seven binary systems (1,1-dimethylethyl methyl ether (MTBE)+2,2,4-trimethylpentane); (1,1-dimethylethyl methyl ether (MTBE) + toluene); (toluene + 2,2,4-trimethylpentane); (toluene + 1-hexene); (toluene + cyclohexane); (2,2,4-trimethylpentane + 1-hexene) and (2,2,4-trimethylpentane + cyclohexane) are reported. Data reduction by Barker's method provides correlations for G(E) using the Margules equation, Wilson, NRTL and UNIQUAC models, which have been applied successfully. We have compared the behaviour in the vapour-liquid equilibrium of the aromatic compounds benzene and toluene and the paraffins heptane and 2.2,4-trimethylpentane. And finally we have modelled a gasoline of five components using the Wilson model, and we have compared the influence of three different ethers used as oxygenated additives in gasolines. (C) 2004 Elsevier B.V. All rights reserved.