Green Solvent Selection Guide for Biobased Organic Acid Recovery

Biobased organic acids constitute an important group of building block chemicals that can be produced from renewable resources, becoming a sustainable alternative to conventional petrochemical-derived commodities. However, due to the growing number of green solvents emerging as extraction media, the proper solvent selection for biomolecule separation from fermentation broths has become a key challenge in the biorefinery industry. The overall aim of this work is to develop a roadmap to select and design green solvents for sustainable downstream processing of biobased organic acids. To this end, a wide range of neoteric solvents (ionic liquids, eutectic solvents, and biobased solvents) were systematically evaluated for the recovery of relevant bio-organic acids through a combination of experimental and COSMO-RS (conductor-like screening model for real solvents) molecular simulation methods. Comprehensive thermodynamic analyses evaluating the organic acid partition coefficients, excess enthalpy contributions, solvent–water affinity, and process spontaneity were performed to elucidate the main mechanism driving the separation process and to provide essential guidelines for further solvent development. On the basis of these findings, a rational screening approach was established to identify suitable solvents for the recovery of structurally different bio-organic acids. Ultimately, this paper provides a green solvent selection guide to design sustainable separation processes for biobased organic acids to serve as valuable platform chemicals to transition toward a biobased economy.