Selective Cleavage of the Aryl Ether Bonds in Lignin for Depolymerization by Acidic Lithium Bromide Molten Salt Hydrate under Mild Conditions

Cracking aryl ether bonds of lignin by γ-valerolactone (GVL) in coordination with acid lithium bromide molten salt system

The chemical bond cleavage of lignin is a research focus for achieving depolymerized lignin for such applications as adhesives, fuels, fertilizers, etc. The depolymerization of an industrially available sustainable material, i.e., industrial alkali lignin, in LiBr·3H2O/HBr-γ-valerolactone (GVL) was systematically investigated in this study. It was observed that using 3/1 mL/g of HBr/lignin and 8/1 mL/g of GVL/lignin at 110 °C for 90 min, i.e., optimized conditions, resulted in lignin derivatives with an Mw of 1889 g/mol and Mn of 895 g/mol. The characteristics of the products were studied using FTIR, NMR, SEM, and DLS techniques. The results confirmed that the Hibbert-ketone end group was formed, while the structure of the aromatic ring was not changed on the depolymerized lignin. After the depolymerization process, the hydroxyl content in lignin increased from 1.91 mmol/g to 2.96 mmol/g. The product derived from the LiBr·3H2O/HBr-GVL depolymerization system displayed a spherical particle morphology. The addition of GVL to lignin depolymerization processes improved the bonding between lignin and inorganic molten salts, thereby promoting the acid-catalyzed cleavage of aryl ether bonds in lignin. Current research supports the conclusion that LiBr·3H2O/HBr-GVL lignin depolymerization is a sustainable and effective chemical pathway for generating depolymerized lignin.

Chemistry of lignin and condensed tannins as aromatic biopolymers

Aromatic biopolymers are the second largest group of biopolymers after polysaccharides. Depolymerization of aromatic biopolymers, as cheap and renewable substitutes for fossil-based resources, has been used in the preparation of biofuels, and a range of aromatic and aliphatic small molecules. Additionally, these polymers exhibit a robust UV-shielding function due to the high content of aromatic groups. Meanwhile, the abundance of phenolic groups in their structures gives these compounds outstanding antioxidant capabilities, making them well-suited for a diverse array of anti-UV and medical applications. Nevertheless, these biopolymers possess inherent drawbacks in their pristine states, such as rigid structure, low solubility, and lack of desired functionalities, which hinder their complete exploitation across diverse sectors. Thus, the modification and functionalization of aromatic biopolymers are essential to provide them with specific functionalities and features needed for particular applications. Aromatic biopolymers include lignins, tannins, melanins, and humic acids. The objective of this review is to offer a thorough reference for assessing the chemistry and functionalization of lignins and condensed tannins. Lignins represent the largest and most prominent category of aromatic biopolymers, typically distinguishable as either softwood-derived or hardwood-derived lignins. Besides, condensed tannins are the most investigated group of the tannin family. The electron-rich aromatic rings, aliphatic hydroxyl groups, and phenolic groups are the main functional groups in the structure of lignins and condensed tannins. Methoxy groups are also abundant in lignins. Each group displays varying chemical reactivity within these biopolymers. Therefore, the selective and specific functionalization of lignins and condensed tannins can be achieved by understanding the chemistry behavior of these functional groups. Targeted applications include biomedicine, monomers and surface active agents for sustainable plastics.

Lignin fractionation and condensation in aromatic-additive-assisted acidic pretreatment and their influence on lignin's effect on the enzymatic hydrolysis

Factors influencing inhibition of lignin on the enzymatic hydrolysis have not been fully elucidated. This study aims to elucidate the effects of lignin fractionation and condensation on its inhibition on enzymatic hydrolysis in aromatic-additive-assisted acidic pretreatment using 2-naphthol (2 N), 2-naphthol-7-sulfonate (NS), and resorcinol (RS). Through simulation reactions of pretreatment and physiochemical analyses of ethanol-extractable lignins (ELs) and cellulolytic enzyme lignins (CELs) from pretreatment, it was observed that 2 N addition in the acidic pretreatment could suppress lignin condensation. This suppression consequently mitigated inhibition of EL-AP-2 N on the enzymatic hydrolysis of Avicel. Simultaneously, addition of NS in the pretreatment can enhance lignin fractionation by facilitating decomposition of lignin into water and ethanol soluble fractions, thereby mitigating inhibition of CEL-AP-NS on the enzymatic hydrolysis. Meanwhile, with RS in the pretreatment, EL-AP-RS and CEL-AP-RS demonstrated the most pronounced inhibition among ELs and CELs. This inhibition may be attributed to the increased phenolic OH groups with the introduction of RS units. A heatmap analysis revealing relationship between lignin characteristics and its inhibition indicated that ELs exhibit reduced inhibition on enzymatic hydrolysis when lignin condensation was suppressed. Conversely, CELs would show diminished inhibitory effects when lignin particle sizes were smaller and lignin fractionation was stronger.

Enhanced Antioxidation and UV-Absorption Ability of Industrial Lignin via Promoting Phenolic Contents and Hydrophilicity

Lignin possesses unique natural antioxidation and UV-absorption abilities, making it a promising ingredient for sunscreen. However, the industrial lignin produced from pulping or bioethanol production generally shows low efficiency due to the limited phenolic hydroxyl content and poor compatibility with sunscreen, respectively. To address this issue, a molten salt hydrate treatment process was carried out for the selective cleavage of ether bonds in industrial lignin. After treatment, a 2-fold increase in phenolic hydroxyl content was observed, and lignin antioxidation efficiency was improved. The intermolecular forces of lignin in water measured by an atomic force microscope showed a significant decrease from -1.46 to 0.46 mN/m, suggesting an efficient increase in lignin hydrophilicity, which promoted lignin compatibility with sunscreen. We converted industrial lignin into colloidal balls, which improved compatibility and dispersion in the cream and more than tripled the sun protection factor compared to the direct addition of industrial lignin.

Advancing Lignocellulosic Biomass Fractionation through Molten Salt Hydrates: Catalyst-Enhanced Pretreatment for Sustainable Biorefineries

Developing a process that performs the lignocellulosic biomass fractionation under milder conditions simultaneously with the depolymerization and/or the upgrading of all fractions is fundamental for the economic viability of future lignin-first biorefineries. The molten salt hydrates (MSH) with homogeneous or heterogeneous catalysts are a potential alternative to biomass pretreatment that promotes cellulose's dissolution and its conversion to different platform molecules while keeping the lignin reactivity. This review investigates the fractionation of lignocellulosic biomass using MSH to produce chemicals and fuels. First, the MSH properties and applications are discussed. In particular, the use of MSH in cellulose dissolution and hydrolysis for producing high-value chemicals and fuels is presented. Then, the biomass treatment with MSH is discussed. Different strategies for preventing sugar degradation, such as biphasic media, adsorbents, and precipitation, are contrasted. The potential for valorizing isolated lignin from the pretreatment with MSH is debated. Finally, challenges and limitations in utilizing MSH for biomass valorization are discussed, and future developments are presented.

Microwave Depolymerization of Lignin via Dynamic Vapor Flow Reaction System: HCOOH as Pretreatment Solvent or Reforming Solvent Vapor

Different forms of HCOOH in the depolymerization system play an important role in governing the monomeric products from lignin. We reported two strategies for the introduction of HCOOH to enrich the monophenols from kraft lignin by microwave-assisted depolymerization. The reaction of lignin models showed that HCOOH was in favor of the cleavage of C-O bonds (β-O-4 typically) and partial C-C bonds (Cα-Cβ). Subsequently, Microwave-assisted depolymerization of lignin with two strategies was conducted via a designed dynamic vapor flow reaction system. Strategy A with HCOOH as pretreatment solvent showed excellent monophenols enrichment with total mass yields of 193.71 mg/g (lignin basis). Strategy B using HCOOH as reforming solvent vapor significantly increased the monophenols selectivity. It presented unique reforming and upgrading performance by generating catechol (42.59 mg/g, lignin basis) and homovanillic acid (17.58 mg/g, lignin basis). This study provided potential strategies for the efficient conversion of kraft lignin into high-value platform chemicals.

One-step conversion of corn stalk to glucose and furfural in molten salt hydrate/organic solvent biphasic system

An effective approach for glucose and furfural production by converting cellulose and hemicelluloses from corn stalk in a biphasic system of molten salt hydrate (MSH) and organic solvent using H2SO4 as catalyst was reported. Results showed that the system with LiBr·3H2O and dichloromethane (DCM) had excellent performance in cellulose and hemicelluloses conversion. Under the optimal reaction conditions (corn stalk:LiBr·3H2O:DCM ratio = 0.35:10:20 g/mL/mL, 0.05 mol/L H2SO4, 120 °C, 90 min), 58.9% glucose and 72.5% furfural were yielded. Meanwhile, lignin was obviously depolymerized by the cleavage of β-O-4' linkages and fractionated with high purity and low molecular weight for potential coproducts. Fluorescence microscopy and confocal Raman microscope displayed that the LiBr·3H2O/DCM treatment caused decreasing intensities in carbohydrate and lignin, suggesting the degradation of the main components of biomass. This research provided a promising biorefinery technology for the comprehensive utilization of corn stalk.

Efficient O-demethylation of lignin-derived aromatic compounds under moderate conditions

Lignin is a potential feedstock to produce renewable aromatic chemicals. However, lignin-derived aromatics are heavily methoxylated, which affects their reactivity in some downstream valorization attempts. Herein, we report an efficient method for the demethylation of the aromatics derived from lignin depolymerization using acidic concentrated lithium bromide (ACLB) under moderate conditions (e.g., 1.5 M HCl, 110 °C, and 2 h). Aromatics with one or two methoxy groups (G-type and S-type), alkyl hydroxyl and carbonyl groups, and electron-donating and electron-withdrawing substituents were used to investigate the demethylation mechanisms. S-type aromatics were demethylated faster than their G-type analogs. Alkyl hydroxyl groups were brominated under the conditions. Carbonyl groups (aldehydes and ketones) promoted unwelcome condensation. Electron-donating substituents promoted demethylation, whereas electron-withdrawing substituents retarded the demethylation. An ortho-carboxylic group enhanced the demethylation because of the formation of a stable intermediate.

Transformation of Corn Stover into Furan Aldehydes by One-Pot Reaction with Acidic Lithium Bromide Solution

Currently, the production of furan aldehydes from raw biomass suffers from low furfural yield and high energy consumption. In this study, a recyclable and practical method was explored for the preparation of furfural from corn stover by the one-pot reaction by acidic lithium bromide solution (ALBS) without pretreatment and enzymolysis. In the ALBS reaction, the furan aldehydes were generated by the degradation of lignocellulose; however, the products were unstable and were further dehydrated to form humins. So, dehydration reaction was inhibited in this study, and the high yield of furan aldehydes was obtained, in which 2.94 g/L of furfural and 2.78 g/L of 5-hydroxymethyl furfural (5-HMF) were generated with high solid loading (10 wt%), the presence of commercial catalyst ZSM-5 and co-solvent tetrahydrofuran (THF) at 140 °C for 200 min. Via this method, almost 100% of hemicellulose was transformed to furfural, and 40.71% of cellulose was transformed to 5-HMF, which was based on the theoretical yield of HMF (8.35 g) from glucose (29.30 g) produced from cellulose. After the reaction, the catalyst ZSM-5 was the main component in the solid residue and kept a suitable performance. THF azeotrope was easily separated from the slurry by evaporation. During the removal of THF, lignin was precipitated from the liquid phase and showed lower molecular weight and abundant active groups, which was a potential feedstock for producing valuable aromatics and polymers. Thus, in a one-pot reaction, the ideal yield of furan aldehydes from raw biomass was obtained on a lab scale, and the catalyst, THF, and LiBr were easily recycled, which provided an option to realize the economical production of sustainable furan aldehydes from raw biomass.

High-Quality Natural Fibers from Cotton Stalk Bark via Limited Alkali Penetration and Simultaneous Accelerated Temperature Rise

High-quality cotton stalk fibers that are both fine and have a high breakage strength are extracted via limited alkali penetration in the glycerol solvent and simultaneous accelerated temperature rise by means of microwave-assisted heating. Alkali is widely used in the extraction of cotton stalk fibers. However, alkali molecules in the aqueous phase penetrate easily into the fiber bundles, resulting in a simultaneous degumming between the inner and outer layers of the fiber bundles. In previous reports, the fibers treated in the aqueous phase present a coarse fineness (51.0 dtex) under mild conditions or have a poor breakage strength (2.0 cN/dtex) at elevated temperatures. In this study, glycerol is chosen as a solvent to reduce the penetration of alkali. Simultaneously, the microwave-assisted heating form is adopted to increase the temperature to 170 °C within 22 s. The inhibited alkali penetration and accelerated temperature rise limited the delignification to the outer layer, resulting in fibers with both appropriate fineness (23.8 dtex) and high breakage strength (4.4 cN/dtex). Moreover, the fibers also exhibit a clean surface and large contact angle. In this paper, we detail a new strategy to extract high-quality lignocellulosic fibers that will be suitable for potential reinforcing applications.

Preparation of magnetic silica supported Brönsted acidic ionic liquids for the depolymerization of lignin to aromatic monomers

Lignin, the most abundant renewable resource of aromatics in nature, is recognized as an alternative for fossil-based fuels and chemicals. Herein, we proposed an efficient method to obtain aromatic monomers...

Efficiently conversion of raw lignocellulose to levulinic acid and lignin nano-spheres in acidic lithium bromide-water system by two-step process

Herein, acidic concentrated lithium bromide-water system was efficiently carried out to synthesize levulinic acid (LA) from raw lignocellulose by two-step treatment. Saccharification was processed in 1st step, and 80.96 wt% glucose and 85.60 wt% xylose were yielded based on their theoretical yield from poplar at 110 °C for 20 min. The hydrolysate after solid residual lignin (SRL) separation was converted into LA and furfural by thermal treatment (130 °C) in the 2nd step, where 67.0 wt% LA and 48.0 wt% furfural were yielded. The SRL in 1st step, with high hydrophobicity and uniform dispersity, was used to prepare lignin nanoparticles (LNPs), which showed tailored size (100-200 nm diameters) and morphology in solid or hollow structure with single hole. Additionally, the residue in 2nd step was suggested as biochar. So far, this study offered a simple pathway for utilization of raw lignocellulose in water system, resulting in high yields of LA and LNPs.

Depolymerization and Demethylation of Kraft Lignin in Molten Salt Hydrate and Applications as an Antioxidant and Metal Ion Scavenger

To improve the reactivity and enrich the functionality of lignin for valorization, kraft lignin was depolymerized and demethylated via cleaving aryl and alkyl ether bonds in acidic lithium bromide trihydrate (∼60% LiBr aqueous solution). It was found that the cleavage of the ether bonds followed the order of β-O-4 ether > aryl alkyl ether in phenylcoumaran > dialkyl ether in resinol > methoxyl (MeO). The depolymerization via β-O-4 cleavage occurred under mild conditions (e.g., <0.5 M HCl at 110 °C), while sufficient demethylation of the lignin needed harsher conditions (>1.5 M HCl). Both depolymerization and demethylation generated new aromatic hydroxyl (ArOH). With 2.4 M HCl, MeO content dropped from 4.85 to 0.95 mmol/g lignin, and ArOH content increased from 2.78 to 5.09 mmol/g lignin. The depolymerized and demethylated kraft lignin showed excellent antioxidant activity and Cr(VI)-scavenging capacity, compared with original kraft lignin and tannins.

Plant celluloses, hemicelluloses, lignins, and volatile oils for the synthesis of nanoparticles and nanostructured materials

A huge variety of plants are harvested worldwide and their different constituents can be converted into a broad range of bionanomaterials. In parallel, much research effort in materials science and engineering is focused on the formation of nanoparticles and nanostructured materials originating from agricultural residues. Cellulose (40-50%), hemicellulose (20-40%), and lignin (20-30%) represent major plant ingredients and many techniques have been described that separate the main plant components for the synthesis of nanocelluloses, nano-hemicelluloses, and nanolignins with divergent and controllable properties. The minor components, such as essential oils, could also be used to produce non-toxic metal and metal oxide nanoparticles with high bioavailability, biocompatibility, and/or bioactivity. This review describes the chemical structure, the physical and chemical properties of plant cell constituents, different techniques for the synthesis of nanocelluloses, nanohemicelluloses, and nanolignins from various lignocellulose sources and agricultural residues, and the extraction of volatile oils from plants as well as their use in metal and metal oxide nanoparticle production and emulsion preparation. Furthermore, details about the formation of activated carbon nanomaterials by thermal treatment of lignocellulose materials, a few examples of mineral extraction from agriculture waste for nanoparticle fabrication, and the emerging applications of plant-based nanomaterials in different fields, such as biotechnology and medicine, environment protection, environmental remediation, or energy production and storage, are also included. This review also briefly discusses the recent developments and challenges of obtaining nanomaterials from plant residues, and the issues surrounding toxicity and regulation.

Monosaccharides and carbon nanosphere obtained by acidic concentrated LiBr treatment of raw crop residues via optimizing the synthesis process

The by-product from acidic concentrated LiBr hydrolyzed (ALBH) crop residues, as ALBH biochar, showed great potential as adsorbent for removing heavy metal pollution. By optimizing the treatment conditions, this study indicated that 22.44% of cellulose was hydrolyzed to glucose, and the residues showed 86.96 mg/g of adsorption capacity to Cr(VI) after T6 treatment of elephant grass. With T3 treatment (5% solid ratio, 0.5 M HCl, at 140 °C for 150 min), the residues from treated elephant grass got 100 mg/g adsorption capability to Cr(VI). Meanwhile, the carbon sphere with uniform, dispersive and in diameter of ~100 nm was formed via the further dehydration and condensation reaction of saccharides. Among the raw feedstocks, the relative high content of cellulose (40.30%) caused elephant grass as the optimal option for carbon spheres production.

Effluent of biomass cooking with active oxygen and solid alkali (CAOSA): component separation, recovery and characterization

Effluent from biomass pretreatment industries affects a substantial proportion of industrial wastewater and can be troublesome to treat. In a new environmentally benign biomass pretreatment approach based on cooking with active oxygen and solid alkali (CAOSA), some precipitates were found to be produced while the effluent (yellow liquor) was treated with alcohol or acid. Based on the precipitation approaches, component contents in CAOSA yellow liquor were successfully made clear, consisting of 57.19 wt% low molecular weight acid salts, 15.47 wt% lignin, 4.30 wt% saccharides and 23.04 wt% inorganic salts. Different organic solvents were tested as the precipitants, and when ethanol was used, over 81 wt% of the compounds in the yellow liquor could be precipitated. Meanwhile, 89.2% of the solid alkali consumed in CAOSA pretreatment could be recovered, showing prospects for primary effluent treatment. Furthermore, CAOSA lignin (CL) was recovered by acid precipitation from yellow liquor. By characterization, CL was found to have lower molecular weight and higher β-O-4 bond (60.05%) ratio than milled wood lignin (MWL, 48.64%), and thus, it might be a more ideal feedstock for further valorization.

An organic solvent precipitation approach is adopted to treat biomass pretreatment effluent and 88.9% solid alkali recovery is reached. With the simple precipitation method, component content and structure in the effluent is also determined.

The residue from the acidic concentrated lithium bromide treated crop residue as biochar to remove Cr (VI)

In this work, the hydrolysis residue produced from the acidic concentrated lithium bromide hydrolysis (ALBH) of wheat straw, corn stover and elephant grass were characterized as biochar. The ALBH biochar as the black power had high content of carbon (49.65-55 wt%), specific surface areas (4.53-7.79 m²/g), porous structures (micropores, mesopores and macropores) and abundant oxygen functional groups (hydroxy, carbonyl, ester and ketone groups). These properties made ALBH biochar as a potential adsorbent for environmental remediation, with relatively high removal efficiency for a variety of heavy metal ions, especially hexavalent chromium (Cr(VI)). Therefore, ALBH technology may be an efficient strategy for synthesis of bio-char along with fermentable sugars, which met the concern of sustainability and green chemistry.

Structural Characterization and Antioxidant Activity of Milled Wood Lignin from Xylose Residue and Corncob

Xylose residue (XR), after diluted acid treatment of corncob, consists of cellulose and lignin. However, structural changes of XR lignin have not been investigated comprehensively, and this has seriously hindered the efficient utilization of lignin. In this study, corncob milled wood lignin (CC MWL), and xylose residue milled wood lignin (XR MWL) were isolated according to the modified milled wood lignin (MWL) method. The structural features of two lignin fractions were thoroughly investigated via fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and two dimensional nuclear magnetic resonance (2D NMR) spectroscopy techniques. XR MWL with higher yield and lower bound carbohydrate contents presented more phenolic OH contents than CC MWL due to partial cleavage of β-O-4. Furthermore, the molecular weights of XR MWL were increased, possibly because of condensation of the lignin during the xylose production. A study on antioxidant activity showed that XR lignin had better radical scavenging ability than that of 2,6-Di-tert-butyl-4-methyl-phenol (BHT) and CC MWL. The results suggested that the lignin in xylose residue, showing great antioxidant properties, has potential applications in food additives.

Influence of Base-Catalyzed Organosolv Fractionation of Larch Wood Sawdust on Fraction Yields and Lignin Properties

Lignocellulose-based biorefineries are considered to play a crucial role in reducing fossil-fuel dependency. As of now, the fractionation is still the most difficult step of the whole process. The objective of this study is to investigate the potential of a base-catalyzed organosolv process as a fractionation technique for European larch sawdust. A solvent system comprising methanol, water, sodium hydroxide as catalyst, and anthraquinone as co-catalyst is tested. The influence of three independent process variables, temperature (443–446 K), catalyst loading (20–30% w/w), and alcohol-to-water ratio (30–70% v/v), is studied. The process conditions were determined using a fractional factorial experiment. One star point (443 K, 30% v/v MeOH, 30% w/w NaOH) resulted in the most promising results, with a cellulose recovery of 89%, delignification efficiency of 91%, pure lignin yield of 82%, residual carbohydrate content of 2.98% w/w, and an ash content of 1.24% w/w. The isolated lignin fractions show promising glass transition temperatures (≥424 K) with high thermal stabilities and preferential O/C and H/C ratios. This, together with high contents of phenolic hydroxyl (≥1.83 mmol/g) and carboxyl groups (≥0.52 mmol/g), indicates a high valorization potential. Additionally, Bjorkman lignin was isolated, and two reference Kraft cooks and a comparison to three acid-catalyzed organosolv fractionations were conducted.

Organosolv Fractionation of Softwood Biomass for Biofuel and Biorefinery Applications

Softwoods represent a significant fraction of the available lignocellulosic biomass for conversion into a variety of bio-based products. Its inherent recalcitrance, however, makes its successful utilization an ongoing challenge. In the current work the research efforts for the fractionation and utilization of softwood biomass with the organosolv process are reviewed. A short introduction into the specific challenges of softwood utilization, the development of the biorefinery concept, as well as the initial efforts for the development of organosolv as a pulping method is also provided for better understanding of the related research framework. The effect of organosolv pretreatment at various conditions, in the fractionation efficiency of wood components, enzymatic hydrolysis and bioethanol production yields is then discussed. Specific attention is given in the effect of the pretreated biomass properties such as residual lignin on enzymatic hydrolysis. Finally, the valorization of organosolv lignin via the production of biofuels, chemicals, and materials is also described.

Rapid and near-complete dissolution of wood lignin at ≤80°C by a recyclable acid hydrotrope

We report the discovery of the hydrotropic properties of a recyclable aromatic acid, p-toluenesulfonic acid (p-TsOH), for potentially low-cost and efficient fractionation of wood through rapid and near-complete dissolution of lignin. Approximately 90% of poplar wood (NE222) lignin can be dissolved at 80°C in 20 min. Equivalent delignification using known hydrotropes, such as aromatic salts, can be achieved only at 150°C or higher for more than 10 hours or at 150°C for 2 hours with alkaline pulping. p-TsOH fractionated wood into two fractions: (i) a primarily cellulose-rich water-insoluble solid fraction that can be used for the production of high-value building blocks, such as dissolving pulp fibers, lignocellulosic nanomaterials, and/or sugars through subsequent enzymatic hydrolysis; and (ii) a spent acid liquor stream containing mainly dissolved lignin that can be easily precipitated as lignin nanoparticles by diluting the spent acid liquor to below the minimal hydrotrope concentration. Our nuclear magnetic resonance analyses of the dissolved lignin revealed that p-TsOH can depolymerize lignin via ether bond cleavage and can separate carbohydrate-free lignin from the wood. p-TsOH has a relatively low water solubility, which can facilitate efficient recovery using commercially proven crystallization technology by cooling the concentrated spent acid solution to ambient temperatures to achieve environmental sustainability through recycling of p-TsOH.

Effective conversion of biomass into bromomethylfurfural, furfural, and depolymerized lignin in lithium bromide molten salt hydrate of a biphasic system

A biphasic system including acidic lithium bromide trihydrate effectively converted lignocellulosic biomass into bromomethylfurfural (BMF), furfural (FF) and depolymerized lignin.