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 apolar aprotic solventthatdonotpossess
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).