Calculation of the size and energy parameters of N-methylpyrrolidone

The activity coefficient of N-methylpyrrolidone (NMP) in the mixture with lube-oil cut is essential for phase equilibrium calculations and for design purposes in the lube-oil extraction units. UNIFAC is an applied effective method for activity coefficient calculations. However, the size and energy parameters for NMP are required for applying the UNIFAC model. In this work, the size parameters for NMP have been calculated by the method of Bondi and the energy parameters between NMP and other functional groups have been obtained. Then, the activity coefficient and phase equilibria calculations have been performed by the UNIFAC model. The results of the calculations have been compared with the experimental data and good agreement has been observed.