Improving the aqueous solubility of poorly soluble hydrophobic
compounds is a topic of great interest to the pharmaceutical, chemical,
and food industries. The poor solubility of these compounds in water
poses a challenge in developing sustainable processes for their extraction,
separation, and formulation. Therefore, in this study, the use as
hydrotropes of biobased solvents such as γ-valerolactone (GVL),
Cyrene, ethyl lactate, and alkanediols (1,2-propanediol, 1,5-pentanediol,
and 1,6-hexanediol) to improve the solubility of two model compounds
(syringic acid and ferulic acid) in water is investigated. The effects
of the concentration and structure of biobased solvents on the solubility
of phenolic compounds in aqueous solutions at (303.2 ± 0.5) K
were studied. The results showed that the aqueous solubility of the
phenolic compounds studied typically increased with the log (K
OW) of the hydrotrope (1,2-propanediol <
Cyrene < 1,5-pentanediol < GVL < ethyl lactate < 1,6-hexanediol)
and the hydrophobicity of the solute; the hydrotropic dissolution
of phenolic compounds is shown to depend on both the hydrotrope and
the solute. This study shows that some biobased solvents, especially
GVL, are excellent hydrotropes. Their renewable nature, low price,
and low toxicity make these results particularly relevant to the field
of extraction and separation of bioactive compounds.