Eco-Friendly Solvents for Bioactives: Solubilization of Hydroxycinnamic Acids in Glycerol-Derived Ethers.

Hydroxycinnamic acids, such as coumaric, ferulic, and caffeic acids, stand out for their pharmacological and cosmetic applications due to their bioactive properties. However, their low solubility in water and conventional solvents can be considered a drawback for their effective utilization. This study investigates the solubility of these acids in renewable glycerol-derived ethers, which exhibit good ecotoxicological profiles and tunable physicochemical properties. Experimental solubility data revealed that monoethers and diethers with shorter alkyl chains significantly enhance the solubility of the studied hydroxycinnamic acids. The findings were further corroborated by COSMO-RS modeling, highlighting the importance of both hydrogen-bond donor capacity and polarity-polarizability in solubility enhancement. Hydrotropic effects of glycerol ethers in water were also experimentally demonstrated, indicating their potential in pharmaceutical and industrial formulations. These results underscore the efficacy of glycerol-derived solvents as sustainable alternatives for solubilizing hydroxycinnamic acids, paving the way for greener and more efficient applications.