Journal of the Chinese Institute of Chemical Engineers, Vol.37, No.4, 329-339, 2006
Effects of cosolvents on the solubility of beta-carotene in supercritical carbon dioxide
The solubilities of beta-carotene in pure supercritical carbon dioxide with, respectively, the cosolvents of ethanol, acetone, and n-hexane were measured using a semi-flow type apparatus and ranged from 15 MPa to 28 MPa under a temperature range of 313.15 K to 333.15 K. With regard to the experimental solubilities in pure supercritical carbon dioxide, the data are consistent with values reported in the literature with a magnitude order from 10(-8) to 10(-7) in mole fraction. The experimental results showed that the cosolvents increased the solubility, and the effect in the order of acetone > n-hexane > ethanol with exceptions under some experimental conditions as described in the paper. The largest enhancement in the solubility by a cosolvent appears at 333.15 K, 15 MPa with 10% n-hexane in the solvent mixture. The experimental solubility data of beta-carotene in CO2 were correlated fairly well with the Peng-Robinson equation of state incorporated with the modified van der Waals mixing rule, and with the method of Debenedetti and Kumar. The experimental data of beta-carotene + CO2 + ethanol, beta-carotene + CO2 + acetone, and beta-carotene + CO2 + n-hexane systems were correlated with the modified empirical equation of Chrastil.