Green Solvent Selection Guide for Biobased Organic Acid Recovery

Abstract

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.

The green solvent: a critical perspective

“…A wealth of additional studies, too many to survey comprehensively, have focussed more narrowly on the replacement of: (i) a single solvent, such as N -methylpyrrolidone (Sherwood et al 2016 ) or N,N- dimethylformamide (Linke et al 2020 ); (ii) a solvent type, such as dipolar aprotics (Duereh et al 2017 ) or chlorinated organics (Jordan et al 2021 ); (iii) a reaction medium for a particular reaction (Avalos et al 2006 ), such as amide coupling (MacMillan et al 2013 ), aldehyde reductive amination (McGonagle et al 2013 ) or the Delépine reaction (Jordan et al 2020 ); (iv) a solvent in a process (Avalos et al 2006 ; Fadel and Tarabieh 2019 ), such as membrane production (Xie et al 2020 ); (v) one or more solvents in a series of products (Isoni et al 2016 ); (vi) one or more solvents in an application, such as cleaning, (Tickner et al 2021 ), lubrication (Dörr et al 2019 ), chromatography (Taygerly et al 2012 ; MacMillan et al 2012 ), or product recovery (López-Porfiri et al 2020 ); (vii) one or more solvents in a technology, such as carbon capture (Borhani and Wang 2019 ), or water-based metal extraction (Binnemans and Jones 2017 ; Peeters et al 2020 ); or (viii) the optimised selection of solvents and anti-solvents in pharmaceutical recrystallization from a defined set of 68 compounds (Tan et al 2019 ).…”

Integration of the Process for Production of Ethyl Acetate by an Enhanced Extraction Process

“…Solvents, such as ethyl acetate, are the substances used in many industrial processes, including the chemical industry. Due to their wide range of application, world demand for solvents is constantly growing [1][2][3]. Increasingly stringent regulations on emissions of harmful pollutants from production processes make the importance of so called "green chemistry" (non-toxic chemicals to the environment and living organisms) well recognized [4].…”

Real-Time Monitoring of Aqueous Organic Reduction Reactions Using Ex Situ Fiber Optic Raman Spectroscopy

“…Engineered or designer solvents, such as ionic liquids, have since found utility for a variety of chemical reactions. However, many of these specialty solvents are too expensive for high volume industrial use. , Consequently, focus has shifted again toward conducting organic reactions in aqueous medium because water is nontoxic, inexpensive, and can be easily handled and disposed of. − However, one significant drawback with the use of water-based reaction media is that most traditional reaction-monitoring spectroscopic techniques are not compatible with an aqueous environment. One exception is Raman spectroscopy, wherein the bands associated with water vibrational modes are mostly located in a spectral range (≥ 3000 cm –1 ) that do not obscure Raman signals associated with many organic functional groups of common interest. , …”

“…However, many of these specialty solvents are too expensive for high volume industrial use. 4,5 Consequently, focus has shifted again toward conducting organic reactions in aqueous medium because water is nontoxic, inexpensive, and can be easily handled and disposed of. 6−12 However, one significant drawback with the use of water-based reaction media is that most traditional reaction-monitoring spectroscopic techniques are not compatible with an aqueous environment.…”