This behavior may be explained considering that hydrogen bonding would constitute one of the most important forces taking into account the chemical structure of the cosolvents and solute studied in this work [18,22,25,28]. In this respect, ethyl lactate can develop hydrogen bonding owing to its hydroxyl and carbonyl group [29] while ethanol only possesses a hydroxyl group. On the other side, ethyl acetate is a polar aprotic solvent that do not possess donor hydrogen atoms and cannot form strong hydrogen bonds.
Thus, in comparison with pure CO2 (see Table 2) caffeine recovery was higher using ethanol or ethyl lactate cosolvents, but with ethyl acetate recoveries were similar and even lower (dynamic mode).