Fecha de publicación: 20/12/2024 Fuente: Polymers Polymers, Vol. 16, Pages 3560: Switchable Solvent for Separation and Extraction of Lignin from Lignocellulose Biomass: An Investigation of Chemical Structure and Molecular Weight
Polymers doi: 10.3390/polym16243560
Authors:
Debao Li
Letian Qi
Magdi E. Gibril
Yu Xue
Guihua Yang
Mengru Yang
Yujie Gu
Jiachuan Chen

Lignin, the most abundant natural aromatic polymer, holds considerable promise for applications in various industries. The primary obstacle to the valorization of lignin into useful materials is its low molecular weight and diminished chemical reactivity, attributable to its intricate structure. This study aimed to treat lignocellulosic biomass using a switchable solvent (DBU–HexOH/H2O) derived from the non-nucleophilic superbase 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU), which efficiently separates and extracts lignin from poplar wood. Additionally, it sought to characterize fundamental properties of the extracted switchable solvent lignin (SSL) and propose a mechanism for its separation. In comparison to milled wood lignin, SSL exhibits a greater molecular weight, superior homogeneity, and enhanced stability. The SSL sample was analyzed using spectroscopies including infrared spectroscopy, nuclear magnetic resonance, and X-ray photoelectron spectroscopy. The findings indicated that the structure of SSL was preserved, with the switchable solvent primarily cleaving the C–C and α-O-4 bonds, resulting in a low hydroxyl content, an elevated H/C ratio, and a reduced O/C ratio. The SSL was successfully prepared to lignin nanoparticles (LNPs) with size range of 531–955 nm. This paper presents a technique for processing lignocellulosic biomass using a switchable solvent, highlighting advancements in lignin’s structure and enhancing its use in the chemical sector.