The experimental values of vapor-liquid equilibrium data at temperatures ranging from 323.22K to 423.09K and pressures up to 4.37 MPa are reported elsewhere [Courtial et al., Fluid PHASE EQUILIBRIA., 2009, 277, 152-161] and were correlated with the binary VLE data regressed using two different thermodynamic models, namely, the UNIFAC and Wilson activity models. The work is also concerned with comparing the closeness of calculated binary VLE data from these models with the theoretical data from PR, SAFT-VR, and PC-SAFT equations of state, calculated in the work of Courtial et al. This research also reports the existence of an azeotrope in the range of temperatures, pressures, and components for the n-butane + methanol system. The Wilson model was found to be sufficient in the investigation of excess Gibbs energy for the n-butane + methanol system for temperatures ranging from 323.22K to 423.09K. The relative deviations (RD) and absolute average deviations (AAD) for vapor compositions and pressures have been calculated by the UNIFAC and Wilson models for the binary system of -butane (1) + methanol (2) for the considered temperature and pressure ranges. The relative volatility of the experimental data has also been analysed.