Advisor(s)
Abstract(s)
The use of glycerol ethers (with alkyl side chain ranging from one to six methyl groups) as
hydrotropes to enhance the solubility of gallic and syringic acids in water was here studied.
These compounds were selected due to their biological and industrial applications and for
serving as model molecules for lignin solubilization. The results obtained were compared
against traditional co-solvents, demonstrating the exceptional hydrotropic ability of glycerol
ethers. Setschenow constants show that the hydrophobicities of both solute and hydrotrope play
an important role in the solubility enhancement by hydrotropy, shedding light into its molecular
mechanism.
The solubility curves of gallic acid and syringic acid in the aqueous glycerol ether solutions
were fitted using a recently proposed statistical thermodynamics-based model. This allowed
the estimation of solute recovery from hydrotropic solution by using water as antisolvent.
Unlike what is usually claimed it is here shown that in some conditions it is impossible to
recover the solute by simply adding water. This analysis paves the way for a rational design
and selection of hydrotropes, in which both solubility enhancement and solute recovery are
critical parameters to be taken into account.
Description
Keywords
Cooperativity Green chemistry Hydrotropy Kirkwood-buff Phenolic acids Setschenow
Pedagogical Context
Citation
Soares, Bruna P.; Abranches, Dinis O.; Sintra, Tânia E.; Leal-Duaso, Alejandro; García, José Ignacio; Pires, Elísabet; Shimizu, Seishi; Pinho, Simão P.; Coutinho, João A.P. (2020). Glycerol ethers as hydrotropes and their use to enhance the solubility of phenolic acids in water. ACS Sustainable Chemistry and Engineering. ISSN 2168-0485. 8:14, p. 5742-5749