Simultaneous determination of partition coefficients of three organic compounds distributed as mixtures between SF-CO2 and water using interfaced SFE-SFC apparatus

A combined SFE-SFC system has enabled the simultaneous determination of the partition coefficient ( K ) values of three organic compounds distributed as mixtures between SF-CO 2 and water phases. The system used a single valve SFE-SFC recirculation interface. The compounds were: o -toluidine, o -cresol and indole prepared as mixtures in aqueous solutions at concentration levels applicable to industrial process waters and of relevance to potential groundwater contamination that may arise from geological carbon capture and storage facilities. Sets of three compound K values were simultaneously obtained at temperatures 313 K, 323 K, 333 K, and five pressures from 8.62 MPa to 22.41 MPa. At each temperature, the SFE vessel pressure was incremented in controlled SF-CO 2 pressure steps applied to a single stirred water sample to rapidly obtain complete series of individual K values. The instrumentation and method demonstrate considerable potential to achieve significant time savings to construct an expanded organic compound K database.