Excess molar volumes, densities and P–T–x phase equilibria for binary mixtures of benzene + toluene, benzene + N-methylformamide (NMF), heptane + octane, toluene + m-xylene and toluene + NMF at 333.15 K and 353.15 K

Abstract Isothermal P – T – x phase equilibria at 333.15 K and 353.15 K for five binary mixtures of benzene + toluene, benzene +  N -methylformamide (NMF), heptane + octane, toluene +  m -xylene and toluene + NMF were obtained at pressures from 0 kPa to 101.3 kPa over the whole composition range and liquid densities of these solutions were measured by using vibrating tube densitometers. The excess molar volumes of the liquid phase were determined and the excess molar volumes behavior indicates that three mixtures of benzene + toluene, heptane + octane and toluene +  m -xylene present positive deviation from ideal solution and two mixtures containing the NMF component display largely negative deviation from ideal solution.