Characterization of Eucalyptus nitens Lignins Obtained by Biorefinery Methods Based on Ionic Liquids

Abstract

Eucalyptus nitens wood samples were subjected to consecutive stages of hydrothermal processing for hemicellulose solubilization and delignification with an ionic liquid, i.e., either 1-butyl-3-methylimidazolium hydrogen sulfate or triethylammonium hydrogen sulfate. Delignification experiments were carried out a 170 °C for 10–50 min. The solid phases from treatments, i.e., cellulose-enriched solids, were recovered by centrifugation, and lignin was separated from the ionic liquid by water precipitation. The best delignification conditions were identified on the basis of the results determined for delignification percentage, lignin recovery yield, and cellulose recovery in solid phase. The lignins obtained under selected conditions were characterized in deep by 31P-NMR, 13C-NMR, HSQC, and gel permeation chromatography. The major structural features of the lignins were discussed in comparison with the results determined for a model Ionosolv lignin.

Eucalyptus red grandis pretreatment with protic ionic liquids: effect of severity and influence of sub/super-critical CO2 atmosphere on pretreatment performance

“…S9 in ESI †). 44 The trends are as expected, the glucan fraction decreases with increasing pretreatment times. The sample of Eucalyptus red grandis used in this study had a high initial glucan content when compared to literature values 39.9-49%.…”

“…It has been reported that during autohydrolysis, polysaccharide hydrolysis evolves uniformly due to the presence of acetic acid catalyst which is formed due to the cleavage of acetyl groups present in the hemicellulosic fraction of some lignocellulosic biomass. 44 It has been shown that the hydrogen sulfate-based ionic liquids perform extremely well, even in the absence of the autohydrolysis step. However, the autohydrolysis step, or equivalent method, might be used in large scale processes to remove the hemicellulosic fraction that will solubilise in the ionic liquid, and degrade during the pretreatment conditions, yielding pseudo-lignins and other degradation products.…”

“…56 From these studies, it is hard to conclude which eucalyptus specie will be more suitable for biofuel production as enzymatic digestibility of Eucalyptus nitens pulps were not reported. 44 However, in terms of pulp composition, both species led to high-cellulose content pulps.…”

“…A high-level assessment of 2G ethanol production, with several feedstocks via diluted acid pretreatment, showed that eucalyptus yielded the lowest ethanol production cost when compared to poplar, straw and switchgrass. 43 IL pretreatment of eucalyptus has been explored with hydrogen sulfate based IL 44 47 The aim of the current study is to achieve high saccharication yields from Eucalyptus red grandis pretreatment with the inexpensive protic IL triethlyammonium hydrogen sulfate with minimum severity (time and temperature). Additionally, we investigate the effect of pressurized CO 2 on the deconstruction during ionoSolv pretreatment.…”

Biomimetic Vanadate and Molybdate Systems for Oxidative Upgrading of Iono- and Organosolv Hard- and Softwood Lignins

“…Two hardwood and two softwood lignins, isolated from Eucalyptus nitens and Pinus pinaster, in form of both organosolv and ionosolv lignins have been selected. These lignins have been reported and characterised before [31][32][33] and were chosen as starting materials for this study also because the structural characterization had revealed noteworthy structural differences between the acetosolv and ionosolv lignin of each biomass. These lignins were used in this study without any further refinements or fractional purifications.…”