Due to the lack of experimental solubility data of caffeine in
the CO2 + EL and CO2 + EAC supercritical solvents, the solubility (Y*)
was estimated as the slope of a theoretical linear behavior of the
OEC between t = 0 and t = 14 min (Table 4). For comparison,the estimated
caffeine solubility in pure CO2 was 0.029% mass, which is
quite in agreement with the experimental solubility measured at
343K and 28.1 MPa (0.023% mass) [35]. These estimated solubilities
presume that, as in the case of the solubility of caffeine in
the liquid solvents [30,31], the solubility of caffeine in CO2 with
ethyl lactate cosolvent is higher than in the case of ethanol or ethyl
acetate cosolvents.