Measurement and modeling of mefenamic acid solubility in supercritical carbon dioxide

The main goal of this study was to measure the solubility of mefenamic acid in supercritical carbon dioxide (SC-CO2) at pressures and temperatures range of 16–40 MPa and 308.15, 318.15, 328.15 and 338.15 K, respectively. The obtained results revealed that the mole fractions were varied in the range of 8.31 × 10−5–5.98 × 10−3 under the different conditions. The obtained results were correlated with four empirical correlations including Chrastil, Mendez-Santiago–Teja (MST), Bartle and Kumar and Johnston (K–J) models. The optimized parameters of these correlations were obtained by the graphical regression. The calculated results show a good consistency between the measured and calculated solubilities for Chrastil, MST, Bartle and Kumar and Johnston models with average absolute relative deviation percent (AARD%) of 5.84%, 3.93%, 4.79%, and 5.20%, respectively. In addition, experimental results were modeled with two equations of state including the Esmaeilzadeh–Roshanfekr (ER) and Peng–Robinson (PR) EoSs which their binary interaction parameters, kij and lij, were optimized by the differential evolution (DE) method. DE is a very simple population based stochastic function minimizer which is very powerful at the same time. The estimated solubilities show maximum AARD% of 21.25% and 30.56% and minimum AARD% of 3.54% and 6.81% were found for the ER and PR-EOS's, respectively.

► Simple static method was successfully used to measure the solubility of mefenamic acid.
► Solubility of mefenamic acid was varied from 8.31 × 10−5 to 5.98 × 10−3 at different operating conditions.
► The experimental data were correlated to four semi-empirical density-based correlations and two EoS's.