Predicting the solubilities of metal acetylacetonates in supercritical CO2: Thermodynamic approach using PC-SAFT

Abstract

Solubilities of metal precursors in supercritical carbon dioxide (scCO2) are needed to effectively design the scCO2-based deposition method. Herein, a method for predicting the solubilities of metal acetylacetonate (acac) precursors in scCO2 was developed using the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state. Three PC-SAFT pure-component parameters viz., the segment diameter, segment number, and dispersion energy, for two metal acetylacetonates (Cr(acac)3 and Cu(acac)2) were determined by adjusting their values to the measured solubilities in organic solvents. The PC-SAFT parameters of Cr(acac)3 and Cu(acac)2 were then applied to predict the experimentally determined metal precursor solubilities in scCO2 from the literature. The PC-SAFT predictions accurately described the experimental solubilities in scCO2 over a wide range of pressures and temperatures even if the binary interaction parameter kij was set to 0. The isobaric solubilities in scCO2 were also calculated with the generalized kij values, which provided a successful PC-SAFT description.