An extraction-based facile method for measuring the solubility of organic solid compounds in supercritical carbon dioxide

Due to its dual gas- and liquid-like properties, supercritical carbon dioxide (scCO2) is considered an excellent solvent for dissolving precursors and penetrating nanoscale pores. After subsequent calcination, uniformly dispersed metal or metal oxide nanoparticles or nanowires can be obtained. Organometallic salts are commonly used precursors in this method because they usually have high solubility in scCO2. Therefore, solubility data are essential for the controllable synthesis of such nanocomposites. This work establishes a facile and accessible method for measuring the solubility of organic solids in scCO2. The solubilities of copper acetylacetonate and cobalt acetylacetonate were obtained at temperatures of 313–333 K and pressures of 11–24 MPa. And the solubilities were within 2.3 × 10−2 to 14.1 × 10−2 g/L for Cu(acac)2 and 6.9 × 10−2 to 13.4 × 10−2 g/L for Co(acac)2. The experimental data were fitted to the semi-empirical model with the AARD values of 4.58% and 2.14% for Cu(acac)2 and Co(acac)2, respectively, and the obtained equations could be used to predict solubility of the same systems in the experimental range.