A Sequential Autohydrolysis-Ionic Liquid Fractionation Process for High Quality Lignin Production

Abstract

In this study, we propose a complete biomass fractionation strategy where all three major biopolymers, namely, cellulose, hemicellulose, and lignin, are separated with higher efficiency and purity. Sequential treatment of hybrid poplar wood using autohydrolysis (160 °C, 60 min) and 1-ethyl-3-methylimidazolium acetate activation (60 °C, 3 h) resulted in significantly improved enzymatic saccharification and fractionated 85% cellulose and 67% hemicellulose. The resulting solid fraction contained 90% (w/w) lignin, which was equal to 71% yield based on the original biomass composition. The proposed two-step pretreatment process improved lignin yield by 77% and 23% compared to the single-stage ionic liquid activation or autohydrolysis, respectively. Structural characterization by 2D nuclear magnetic resonance spectroscopy and small-angle neutron scattering revealed that the isolated lignin sustained minimal modifications to interunit linkages and exhibited high thermotolerance as well as unique functionality, thereby highlighting the benefits of this process for lignin fractionation.

Advances in Small Angle Neutron Scattering on Polysaccharide Materials

“…In conclusion, the abundance of published studies of SANS-analyzed cellulose/plant nanostructures [ 91 , 92 , 93 , 94 , 95 , 96 , 97 ] demonstrates the importance of the technique for deeper understanding of these systems and future development of novel environment-friendly materials.…”

Metal-based ionic liquids: effective catalysts in aqueous media for the selective production of vanillin from alkali lignin at room temperature

“…The ILs exhibi- ted high cell wall penetration, which improves solubilization, depolymerization, and conversion of various biomass to renewable chemicals and materials. 27,28 It has to be mentioned that along with lignocellulose biomass fractionation, 29 the ILs also can act as a catalyst by choosing specific coordinating, noncoordinating as well as metal halide-based anions. 30 In addition to stronger solubilizing power for different types of lignin biomass, ILs also make the process more sustainable by increasing the catalyst's activity by stabilizing the in situ generated intermediate.…”

First evaluation of multifunctional poly(ionic liquid)s as novel strong bases in directional efficient valorization of lignin

“…It must be emphasized that the variable anions and cations of ILs make it achieve the specic goal, followed by broadening their applications. [22][23][24] In addition, there are a few literature studies on lignin valorization over ILs, and quite surprisingly, catalytic lignin valorization over ILs with Brønsted-Lewis dibasic sites has remained largely underexplored to date. Addressing vexing challenges of the desired ILs containing Brønsted-Lewis dibasic sites, i.e., the difficult of separation from complex mixtures and easy deliquescence, would signicantly boost their efficient applications in many elds.…”