Vapour–liquid equilibrium at T = 308.15 K for binary systems: Dibromomethane + n-heptane, bromotrichloromethane + n-heptane, bromotrichloromethane + dibromomethane, bromotrichloromethane + bromochloromethane and dibromomethane + bromochloromethane. Experi

• Phase and volumetric behaviour of the binary systems containing polyhalomethanes or n-heptane have been studied.
• Isothermal vapour–liquid equilibrium data at T = 308.15 K were determined.
• Molar excess Gibbs energies were calculated.
• VLE and density data were modelled using Peng–Robinson and PC-SAFT equations of state.

In this paper, the isothermal vapour–liquid equilibrium (VLE) at T = 308.15 K have been measured for liquid binary systems dibromomethane + n-heptane, bromotrichloromethane + n-heptane, bromotrichloromethane + dibromomethane, bromotrichloromethane + bromochloromethane and dibromomethane + bromochloromethane by a dynamic method. The VLE data have been reduced using the Redlich–Kister equation taking into consideration the vapour phase imperfection in terms of 2nd molar virial coefficients and molar excess Gibbs energies, GmE, have been calculated. The experimental GmE is positive for all systems presenting the greatest value for dibromomethane + n-heptane and a negligible value for dibromomethane + bromochloromethane system. From our experimental data and those reported in the literature, phase and volumetric behaviour of the binary systems containing dibromomethane, bromochloromethane, bromotrichloromethane or n-heptane have been modelled. Two equations of state, EoS, of different formulation have been used obtaining a good agreement for all systems. The mean relative deviations for the studied properties are MRD (P) = 1.57%, AAD (y) = 0.0116 and MRD (ρ) = 0.55% for Peng–Robinson EoS, and MRD (P) = 1.20%, AAD (y) = 0.0093 and MRD (ρ) = 0.38% for PC-SAFT EoS.

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