A predictive toolset for the identification of effective lignocellulosic pretreatment solvents: a case study of solvents tailored for lignin extraction

Abstract

Systematic approach for predicting lignin extraction and studying mechanistic effects using computational chemistry and experimental correlations.

Prediction of solubility parameters of lignin and ionic liquids using multi-resolution simulation approaches

“…76 The higher lignin extraction directly correlated with an increase in enzymatic saccharification efficiency (sugar yield) of pretreated lignocellulose. 71 From the HSP point of view, ZnCl 2 –EG had a lower RED of lignin (RED = 0.48) than ZnCl 2 –Gly (0.75), indicating stronger interaction energies between lignin and ZnCl 2 –EG and predicting that ZnCl 2 –EG would efficiently extract lignin from biomass and result in higher sugar yields, which is in agreement with the results of Das et al . 76 Based on the solubility parameters of lignin, it was also speculated that both vdW and electrostatic interactions played a predominant role in the dissolution of lignin, whereas in the case of cellulose and hemicellulose, the electrostatic interactions govern the dissolution process in ILs/DES.…”

“…Recently, Achinivu et al (2021) studied the delignification of sorghum biomass using different molecular solvents such as amines and organic solvents. 71 Hansen and Björkman reported lignin solubility parameters ( δ p = 14.9 MPa 1/2 , δ h = 16.9 MPa 1/2 , and δ d = 21.9 MPa 1/2 ) do not correlate with experimental delignification. However, Thielemans and Wool (2005) 40 reported HSP values of lignin ( δ p = 13.5 MPa 1/2 , δ h = 11.3 MPa 1/2 , and δ d = 16.7 MPa 1/2 ) correlated with biomass delignification results using amines and organic solvents.…”

A review on organosolv pretreatment of softwood with a focus on enzymatic hydrolysis of cellulose

“…For polar molecules and mixture of solvents, Hansen and Björkman [46] proposed three different intermolecular interactions such as dispersive (δ D ), polar (δ p ) and hydrogen bonding (δ H ) which will affect solubility of lignin in a solvent or mixture of solvents. However, Hansen solubility parameter alone cannot explain lignin dissolution since the values are used to measure the intermolecular affinity between solvent and lignin but do not account for their intramolecular affinities [47,48]. The Hildebrand (δ1) and Hansen values of different organic solvents commonly used in the organosolv pretreatment of softwood are listed in Table 1, showing ethanol as a good solvent, generally for lignocellulosic biomass.…”

“…δ value units are (J/cm 3 ) -1/2 . The Hildebrand (δ1) and Hansen solubility values are taken from references[45][46][47][48]…”

Revisiting Theoretical Tools and Approaches for the Valorization of Recalcitrant Lignocellulosic Biomass to Value-Added Chemicals

“…Typically, in biomass pretreatment, quantum chemical (QC) and MD simulations have been adapted to understand the interactions of the various biomass components with the pretreatment solvent, which in turn helps to understand and predict the fractionation abilities of the solvent (or solvent class) under consideration (Table 1). Also, pre-existing solubility parameters such as Hildebrand (Quesada-Medina et al, 2010), Hansen solubility parameters (HSP) (Hansen, 2007;Cheng et al, 2018), and Conductor like Screening Model for Real Solvents (COSMO-RS) models have been extensively studied for several chemical pretreatment technologies employing organic solvents, deep eutectic solvents, and ionic liquids (Balaji et al, 2012;Casas et al, 2013;Achinivu et al, 2021). Recently, ionic liquids (salts possessing organic cations with a melting point below 100 °C) have attracted significant attention as a promising pretreatment solvent.…”