Measurement and Correlation for the Solid Solubility of Antioxidants <scp>d</scp>-Isoascorbic Acid and Calcium <scp>l</scp>-Ascorbate Dihydrate in Supercritical Carbon Dioxide

The central task of this research is devoted to the measurement of the solubility of two antioxidants—d-isoascorbic acid and calcium l-ascorbate dihydrate—in supercritical carbon dioxide. The experiment, using a semiflow type apparatus, takes data at various temperatures, over pressures ranging from 12 MPa to 24 MPa. The acquired data are then processed numerically—with the aid of semiempirical equations proposed by Chrastil and by Mendez-Santiago and Teja—to find the correlated relationship. The correlated results from both equations yield satisfactory results with an average absolute relative deviation (AARD) under 5 % when optimally fitted parameters are chosen.