Separation and model correlation for p-nitroaniline and m-nitroaniline mixture with subcritical R134a

Abstract

To evaluate the separation feasibility of subcritical 1,1,1,2-tetrafluoroethane (sub-R134a) for mixture of p-nitroaniline (p-NA) and m-nitroaniline (m-NA), the separating effect and equilibrium solubility of p-NA and m-NA in both sub-R134a binary and ternary system are measured with static method at 308, 318, 328 K and (5–18) MPa for the first time. The effect of temperature, pressure, solvent density, dipole moment, molecular volume, and intermolecular forces on solubility are analyzed; in addition, the separating effect and solute solubility are compared with those in SCCO2. At 318 K and 18.0 MPa, the separation efficiency of sub-R134a for the solute mixture reaches to the maximum of 87.89%.Semi-empirical models, including Chrastil, A-L, K-J and S-S models for binary system, and González, Sovová, M-M-T, and Z-J models for ternary system, are used for correlating the experimental solubility. The satisfactory correlated results are obtained with the AARD value ranging from 4.85% to 11.27%.