Solubilities in supercritical carbon dioxide of (2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-ol and (2S)-5,7-dihydroxy-2-(4-hydroxyphenyl)chroman-4-one (Naringenin)

Abstract

We measured the solubility in supercritical carbon dioxide (CO2) of farnesol [(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-ol] and naringenin [(2S)-5,7-dihydroxy-2-(4-hydroxyphenyl)chroman-4-one] using an static-analytic method (a high-pressure static equilibrium cell coupled to an HPLC). The molar fraction of farnesol in the saturated CO2-rich phase increased between y2 = 0.13 • 10-3 at 333 K and 11.4 MPa to y2 = 1.91 • 10-3 at 333 K and 26.0 MPa for farnesol, and from y2 = 0.49 • 10-5 at 313 K to 10.3 MPa to y2 = 1.65 • 10-5 at 333 K and 44.5 MPa for naringenin. The average error of our measurements was about 25 %. Farnesol had an end-temperature cross-over point at approximately 17 MPa, whereas naringenin exhibited a monotonous increase in solubility with both temperature and pressure. The differences in solubility between farnesol, naringenin, and other sesquisterpenes or flavonoids reported in literature were partially explained by differences in molecular weight and polarity between solutes. We correlated experimental data as a function of the system temperature and pressure, and the density of the solvent, using a literature model that also showed the auto-consistency of the data for CO2 densities above 412 kg/m3 for naringenin.