Experimental measurements and thermodynamic modeling of Coumarin-7 solid solubility in supercritical carbon dioxide: Production of nanoparticles via RESS method

Abstract

For the first time, solubility of coumarin-7 dye (C7) in supercritical carbon dioxide (SC-CO2) was measured in temperature and pressure ranges of (308–338) K and (90–330) bar, respectively, for binary (C7-CO2) and ternary systems (C7-CO2-methanol). Mole fractions were determined to range from 0.415 × 10−5 to 1.009 × 10−5 and 0.1089 × 10−4 to 1.2007 × 10−4 for binary and ternary systems, respectively. The solubility data was correlated using two thermodynamic models, namely quadrupolar cubic plus association theory (qCPA) and perturbed-chain polar statistical associating fluid theory (PCP-SAFT). Continuing with the research, the rapid expansion of supercritical solution (RESS) process was used to produce coumarine-7 nanoparticles. Effects of temperature, pressure, nozzle diameter, and spraying distance on the particle size were investigated. For this purpose, unprocessed and processed particles were characterized by FTIR, XRD, DSC, SEM, and DLS. A significant decline (21.37 ≤ x50 ≤ 224.13 nm) was observed in the final particle size, as compared to the original one (40.35 μm).