Binary equilibrium behavior for the N,N-dimethylaniline and N,N-diethylaniline in supercritical carbon dioxide

The thermodynamic equilibrium properties of two components, namely, N,N-dimethylaniline (NNDM) and N,N-diethylaniline (NNDE), in supercritical carbon dioxide (S-CO₂) were reported. Data determinations were performed through the static-type method from 313.2 to 393.2 K and 4.70 to 24.90 MPa. The results obtained indicated that the solubility of CO₂ increased monotonically with the increase in system temperature and mole fraction of NNDM and NNDE in binary (solute + solvent) mixtures. The solubility curve of NNDM and NNDE in the S-CO₂ + NNDM and S-CO₂ + NNDE system increased with respect to the increasing temperature at a constant pressure. The S-CO₂ + NNDM and S-CO₂ + NNDE models corresponded to type-I phase behavior. Moreover, laboratory results of both systems were adequately correlated with the Peng-Robinson equation of state. The rmsd (%) of S-CO₂ + NNDM [k_ij = 0.075, η_ij = −0.070] and S-CO₂ + NNDE [k_ij = 0.078, η_ij = −0.070] models working with two factors established at 353.2 K were noted as 7.50% and 7.08%, respectively.