Enhancement of Lignin Extraction of Poplar by Treatment of Deep Eutectic Solvent with Low Halogen Content

A novel choline-based deep eutectic solvent (DES) with low halogen content—namely choline lactate-lactic acid (CLL)—was synthesized by replacing the chloride anion with lactate anion in choline chloride-lactic acid (CCL). CLL and CCL treatments were conducted at 140 °C for 12 h with hydrogen bond acceptor/hydrogen bond donor =1/10, thereafter composition analysis and characterizations of the lignin extracted by DES treatment (DES lignin) and the solid residue were carried out. The proposed low halogen content DES presented an improved lignin extraction efficiency. The CLL treatment extracted 90.13% of initial lignin from poplar, while CCL extracted 86.02%. In addition, the CLL treatment also provided DES lignin with an improved purity (91.17%), lower molecular weight (Mw/Mn=1805/971 g/mol) and more concentrated distribution (polydispersity index=1.86). The efficient lignin extraction was mainly ascribed to the cleavage of β-O-4 bonds in lignin macromolecule, especially in the guaiacyl units, thereby breaking them into smaller molecules, facilitating the lignin extraction. The replacement of chloride anion allowed CLL acting as a more efficient DES to interact with lignin macromolecules, thus providing lignin with higher uniformity and suitable molecular weight. The low halogen content DES system proposed in present work could benefit the fractionation of biomass, improve the valorization of lignin compounds and facilitate industrial process in the downstream.

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Fabrication of Magnetic Catalyst Fe3O4-SiO2-V3 and Its Application on Lignin Extraction from Corncob in Deep Eutectic Solvent

Polymers ◽

10.3390/polym13101545 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1545

Author(s):

Maonan Yuan ◽

Zhen Wang ◽

Yu Liu ◽

Guihua Yang

Keyword(s):

Molecular Weight ◽

Choline Chloride ◽

Average Molecular Weight ◽

Deep Eutectic Solvent ◽

Reaction System ◽

2D Nmr ◽

Number Average Molecular Weight ◽

Batch Experiments ◽

Weight Average Molecular Weight ◽

Lignin Extraction

Fe3O4-SiO2-V3 was prepared by deposited H6PMo9V3O40 on Fe3O4-SiO2 and employed as a catalyst to extract lignin from corncob in deep eutectic solvent (choline chloride/lactic acid = 1/10). Batch experiments were conducted in an autoclave under the conditions of 500 kPa, 90–130 °C and 15 h, while the dosage of the catalyst was set as a variable. Results indicated that the catalyst could effectively improve the qualities of the lignin, while the characteristics of the lignin showed prominent changes with the participation of the catalyst: the extraction rate increased from 71.65% to 98.13%, the purity was improved from 85.62% to 97.09%, and both the number average molecular weight and the weight average molecular weight also decreased significantly. Besides, the molecular distribution of the lignin achieved from the CC-LA-Fe-Si-V3 reaction system was found to be more highly concentrated (Polydispersity index = 1.746). Results from 2D NMR HSQC analysis indicated that lignin fractions achieved from the CC-LA-Fe-Si-V3 system showed distinct destruction involving C2-H2 in guaiacyl units (G), C5-H5 in guaiacyl units (G), and the Cγ-Hγ in γ-hydroxylated β-O-4′ substructures, but little changes in the Cγ-Hγ in phenylcoumaran substructures.

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Deep eutectic solvent pretreatment for enhancing biochemical conversion of switchgrass

10.32469/10355/62347 ◽

2017 ◽

Author(s):

◽

Maryam Al Ameri

Keyword(s):

Hydrogen Bond ◽

Acetic Acid ◽

Choline Chloride ◽

Deep Eutectic Solvent ◽

Deep Eutectic Solvents ◽

Green Solvent ◽

Biomass Recalcitrance ◽

Hydrogen Bond Donor ◽

Excellent Performance ◽

Hydrogen Bond Acceptor

In this study, green solvent-based pretreatment was developed for improving the conversion of switchgrass to acetoin. Deep eutectic solvents (DESs), comprising choline chloride (ChCl) as a hydrogen-bond acceptor (HBA) and various chemical as a hydrogen-bond donor (HBD), were used to pretreat switchgrass. Different HBD groups, including polyalcohol, amid, diazole, and carboxylic acid, were used to synthesize DESs. The DESs using ChCl-formic acid and ChCl-lactic acid-acetic acid showed excellent performance in enhancing switchgrass digestibility. The obtained hydrolysate was successfully detoxified by using overliming detoxification, which was further used for acetoin fermentation by Bacillus licheniformis (NRRL B-642). The yield and titer of the produced acetoin were 0.377 g/g and 19.6 g/L, respectively. Our research demonstrates that DES pretreatment is an effective method for reducing biomass recalcitrance and improving the conversion of biomass into chemicals.

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Deep eutectic solvent-based emulsification liquid–liquid microextraction for the analysis of phenoxy acid herbicides in paddy field water samples

Royal Society Open Science ◽

10.1098/rsos.202061 ◽

2021 ◽

Vol 8 (3) ◽

Author(s):

Nur ‘An Nisaa Mohamad Yusoff ◽

Nurul Yani Rahim ◽

Rania Edrees Adam Mohammad ◽

Noorfatimah Yahaya ◽

Mazidatulakmam Miskam

Keyword(s):

Hydrogen Bond ◽

Water Samples ◽

Paddy Field ◽

Choline Chloride ◽

Deep Eutectic Solvent ◽

Hydrogen Bond Acceptor ◽

Extraction Solvent ◽

Phenoxy Acid Herbicides ◽

Acid Herbicides ◽

Liquid Microextraction

An emulsification liquid–liquid microextraction (ELLME) method was successfully developed using phenolic-based deep eutectic solvent (DES) as an extraction solvent for the determination of phenoxy acid herbicides, 3,6-dichloro-2-methoxybenzoic acid (dicamba) and 2-methyl-4-chlorophenoxyacetic acid (MCPA) in environmental water samples. Five different phenolics-based DESs were successfully synthesized by using phenol (DES 1), 2-chlorophenol (DES 2), 3-chlorophenol (DES 3), 4-chlorophenol (DES 4) and 3,4-dichlorophenol (DES 6) as the hydrogen-bond donor (HBD) and choline chloride as the hydrogen-bond acceptor (HBA). The DESs were mixed at 1 : 2 ratio. A homogeneous solution (clear solution) was observed upon the completion of successful synthesis. The synthesized DESs were characterized by using Fourier transform infrared and nuclear magnetic resonance (NMR). Under optimum ELLME conditions (50 µl of DES 2 as extraction solvent; 100 µl of THF as emulsifier solvent; pH 2; extraction time 5 min), enrichment factor obtained for dicamba and MCPA were 43.1 and 59.7, respectively. The limit of detection and limit of quantification obtained for dicamba were 1.66 and 5.03 µg l −1 , respectively, meanwhile for MCPA were 1.69 and 5.12 µg l −1 , respectively. The developed ELLME-DES method was applied on paddy field water samples, with extraction recoveries in the range of 79–91% for dicamba and 82–96% for MCPA.

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Esterification of Lignin Isolated by Deep Eutectic Solvent Using Fatty Acid Chloride, and Its Composite Film with Poly(lactic acid)

Polymers ◽

10.3390/polym13132149 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2149

Author(s):

Chan-Woo Park ◽

Song-Yi Han ◽

Rajkumar Bandi ◽

Ramakrishna Dadigala ◽

Eun-Ah Lee ◽

...

Keyword(s):

Lactic Acid ◽

Fatty Acid ◽

Composite Film ◽

Acid Chloride ◽

Pinus Densiflora ◽

Choline Chloride ◽

Deep Eutectic Solvent ◽

Morphological Characteristics ◽

Poly Lactic Acid ◽

Fatty Acid Chloride

In this study, the effect of lignin esterification with fatty acid chloride on the properties of lignin and lignin/poly(lactic acid) (PLA) composites was investigated. Lignocellulose (Pinus densiflora S. et Z.) was treated using a deep eutectic solvent (DES) with choline chloride (ChCl)/lactic acid (LA). From the DES-soluble fraction, DES-lignin (DL) was isolated by a regeneration process. Lignin esterification was conducted with palmitoyl chloride (PC). As the PC loading increased for DL esterification, the Mw of esterified DL (EDL) was increased, and the glass transition temperature (Tg) was decreased. In DL or EDL/PLA composite films, it was observed that EDL/PLA had cleaner and smoother morphological characteristics than DL/PLA. The addition of DL or EDL in a PLA matrix resulted in a deterioration of tensile properties as compared with neat PLA. The EDL/PLA composite film had a higher tensile strength and elastic modulus than the DL/PLA composite film. DL esterification decreased water absorption with lower water diffusion coefficients. The effect of lignin esterification on improving the compatibility of lignin and PLA was demonstrated. These results are expected to contribute to the development of high-strength lignin composites.

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Doubly ionic hydrogen bond interactions within the choline chloride–urea deep eutectic solvent

Physical Chemistry Chemical Physics ◽

10.1039/c6cp02815b ◽

2016 ◽

Vol 18 (27) ◽

pp. 18145-18160 ◽

Cited By ~ 143

Author(s):

Claire R. Ashworth ◽

Richard P. Matthews ◽

Tom Welton ◽

Patricia A. Hunt

Keyword(s):

Hydrogen Bond ◽

Hydrogen Bonding ◽

Computational Analysis ◽

Choline Chloride ◽

Deep Eutectic Solvent ◽

Hydrogen Bond Interactions

Computational analysis indicates flexibility and diversity in the hydrogen bonding, but limited charge delocalisation, within the choline chloride–urea eutectic.

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Deep eutectic solvent delignification: Impact of initial lignin

BioResources ◽

10.15376/biores.12.4.7301-7310 ◽

2017 ◽

Vol 12 (4) ◽

pp. 7301-7310

Author(s):

Veronika Majová ◽

Silvia Horanová ◽

Andrea Škulcová ◽

Jozef Šima ◽

Michal Jablonský

Keyword(s):

Lactic Acid ◽

Oxalic Acid ◽

Lignin Content ◽

Choline Chloride ◽

Deep Eutectic Solvent ◽

Deep Eutectic Solvents ◽

Kappa Number ◽

Kraft Pulps ◽

Oxygen Delignification ◽

Detailed Understanding

This study aimed to resolve the issue of the lack of detailed understanding of the effect of initial lignin content in hardwood kraft pulps on pulp delignification by deep eutectic solvents. The authors used Kappa number of the concerned pulp, intrinsic viscosity, and selectivity and efficiency of delignification as the parameters of the effect. The pulp (50 g oven dry pulp) was treated with four different DESs systems based on choline chloride with lactic acid (1:9), oxalic acid (1:1), malic acid (1:1), and system alanine:lactic acid (1:9); the results were compared to those reached by oxygen delignification. The results showed that the pulp with a higher initial lignin content had a greater fraction of easily removed lignin fragments.

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Facilely reducing recalcitrance of lignocellulosic biomass by a newly developed ethylamine-based deep eutectic solvent for biobutanol fermentation

Biotechnology for Biofuels ◽

10.1186/s13068-020-01806-9 ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Guochao Xu ◽

Hao Li ◽

Wanru Xing ◽

Lei Gong ◽

Jinjun Dong ◽

...

Keyword(s):

Hydrogen Bond ◽

Lactic Acid ◽

Lignocellulosic Biomass ◽

Fossil Fuels ◽

Deep Eutectic Solvent ◽

Deep Eutectic Solvents ◽

Specific Yield ◽

Green Solvents ◽

Hydrogen Bond Donor ◽

Total Sugars

Abstract Background Biobutanol is promising and renewable alternative to traditional fossil fuels and could be produced by Clostridium species from lignocellulosic biomass. However, biomass is recalcitrant to be hydrolyzed into fermentable sugars attributed to the densely packed structure by layers of lignin. Development of pretreatment reagents and processes for increasing surface area, removing hemicellulose and lignin, and enhancing the relative content of cellulose is currently an area of great interest. Deep eutectic solvents (DESs), a new class of green solvents, are effective in the pretreatment of lignocellulosic biomass. However, it remains challenging to achieve high titers of total sugars and usually requires combinatorial pretreatment with other reagents. In this study, we aim to develop novel DESs with high application potential in biomass pretreatment and high biocompatibility for biobutanol fermentation. Results Several DESs with betaine chloride and ethylamine chloride (EaCl) as hydrogen bond acceptors were synthesized. Among them, EaCl:LAC with lactic acid as hydrogen bond donor displayed the best performance in the pretreatment of corncob. Only by single pretreatment with EaCl:LAC, total sugars as high as 53.5 g L−1 could be reached. Consecutive batches for pretreatment of corncob were performed using gradiently decreased cellulase by 5 FPU g−1. At the end of the sixth batch, the concentration and specific yield of total sugars were 58.8 g L−1 and 706 g kg−1 pretreated corncob, saving a total of 50% cellulase. Utilizing hydrolysate as carbon source, butanol titer of 10.4 g L−1 was achieved with butanol yield of 137 g kg−1 pretreated corncob by Clostridium saccharobutylicum DSM13864. Conclusions Ethylamine and lactic acid-based deep eutectic solvent is promising in pretreatment of corncob with high total sugar concentrations and compatible for biobutanol fermentation. This study provides an efficient pretreatment reagent for facilely reducing recalcitrance of lignocellulosic materials and a promising process for biobutanol fermentation from renewable biomass.

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Saffron Processing Wastes as a Bioresource of High-Value Added Compounds: Development of a Green Extraction Process for Polyphenol Recovery Using a Natural Deep Eutectic Solvent

Antioxidants ◽

10.3390/antiox8120586 ◽

2019 ◽

Vol 8 (12) ◽

pp. 586 ◽

Cited By ~ 15

Author(s):

Achillia Lakka ◽

Spyros Grigorakis ◽

Ioanna Karageorgou ◽

Georgia Batra ◽

Olga Kaltsa ◽

...

Keyword(s):

Hydrogen Bond ◽

Maximum Yield ◽

Deep Eutectic Solvent ◽

Value Added ◽

Extraction Process ◽

Mass Spectrometry Analysis ◽

Molar Ratio ◽

Optimal Conditions ◽

Hydrogen Bond Acceptor ◽

Natural Deep Eutectic Solvent

The current investigation was undertaken to examine saffron processing waste (SPW) as a bioresource, which could be valorized to produce extracts rich in antioxidant polyphenols, using a green, natural deep eutectic solvent (DES). Initially, there was an appraisal of the molar ratio of hydrogen bond donor/hydrogen bond acceptor in order to come up with the most efficient DES composed of L-lactic acid/glycine (5:1). The following step was the optimization of the extraction process using response surface methodology. The optimal conditions thus determined were a DES concentration of 55% (w/v), a liquid-to-solid ratio of 60 mL g−1, and a stirring speed of 800 rounds per minute. Under these conditions, the extraction yield in total polyphenols achieved was 132.43 ± 10.63 mg gallic acid equivalents per g of dry mass. The temperature assay performed within a range of 23 to 80 °C, suggested that extracts displayed maximum yield and antioxidant activity at 50–60 °C. Liquid chromatography-mass spectrometry analysis of the SPW extract obtained under optimal conditions showed that the predominant flavonol was kaempferol 3-O-sophoroside and the major anthocyanin delphinidin 3,5-di-O-glucoside. The results indicated that SPW extraction with the DES used is a green and efficient methodology and may afford extracts rich flavonols and anthocyanins, which are considered to be powerful antioxidants.

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Review on Carbon Dioxide Absorption by Choline Chloride/Urea Deep Eutectic Solvents

Advances in Chemistry ◽

10.1155/2018/2675659 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6 ◽

Cited By ~ 15

Author(s):

Rima J. Isaifan ◽

Abdukarem Amhamed

Keyword(s):

Carbon Dioxide ◽

Hydrogen Bond ◽

Ionic Liquids ◽

Choline Chloride ◽

Deep Eutectic Solvents ◽

Absorption Capacity ◽

Carbon Dioxide Absorption ◽

Hydrogen Bond Donor ◽

Separation Processes ◽

Hydrogen Bond Acceptor

In the recent past few years, deep eutectic solvents (DESs) were developed sharing similar characteristics to ionic liquids but with more advantageous features related to preparation cost, environmental impact, and efficiency for gas separation processes. Amongst many combinations of DES solvents that have been prepared, reline (choline chloride as the hydrogen bond acceptor mixed with urea as the hydrogen bond donor) was the first DES synthesized and is still the one with the lowest melting point. Choline chloride/urea DES has proven to be a promising solvent as an efficient medium for carbon dioxide capture when compared with amine alone or ionic liquids under the same conditions. This review sheds light on the preparation method, physical and chemical characteristics, and the CO2 absorption capacity of choline chloride/urea DES under different temperatures and pressures reported up to date.

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