Experimental measurements and modeling of curcumin solubility in CO2-expanded ethanol

- Novel experimental data for the solubility of curcumin in CO2-expanded ethanol.
- New-built equipment setup for solubility measurements of compounds with high molar absorptivity.
- Higher solubility of curcumin in CO2-expanded ethanol mixtures was obtained at smallest CO2 content and highest temperature.
- Thermal degradation of curcumin was negligible during the solubility measurements.
- The modification of Chrastil model correlated well the experimental data of solubility.

Carbon dioxide expanded liquids (CXLs) is a relatively recent type of solvent used in separation processes such as extraction. It combines the benefits of high solubility in the organic liquid with enhanced mass transfer mediated by the compressed CO2. In this work, we investigate the solubility of curcumin in CO2-expanded ethanol and for this purpose an equipment setup was built and used for experimental measurements at the temperatures of 308 and 323 K and the pressure range of 10-30 MPa. The amount of CO2 added to ethanol was varied between 10 and 50 mol%. Results show that the highest solubility of curcumin was obtained at the highest temperature and the lowest amounts of CO2 (10 mol%) in the mixture. Moreover, the new-built equipment setup allows the determination of the solubility for compounds with high molar light absorptivity such as curcumin. The experimental data was correlated using PR-EOS and the modified Chrastil model.

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