Possible dissolution mechanism of alkali lignin in lactic acid-choline chloride under mild conditions

Liu, Zhuang; Hou, Yi; Hu, Song-Qing; Li, Youming

doi:10.1039/d0ra07808e

Cited by 16 publications

(6 citation statements)

References 27 publications

(30 reference statements)

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“…It is based on the principle that the reaction of isophosphotungstate—molybdate with phenolic hydroxyl groups—appears blue and is strongly proportional to the number of total phenolic hydroxyl groups, and is suitable for spectrophotometric determination. This method allows a rapid and simple determination of phenolic hydroxyl groups in lignin [ 28 ].…”

Section: Resultsmentioning

confidence: 99%

Comparison of the Degradation Performance of Seven Different Choline Chloride-Based DES Systems on Alkaline Lignin

et al. 2022

Polymers

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Lignin is a natural polymer second only to cellulose in natural reserves, whose structure is an aromatic macromolecule composed of benzene propane monomers connected by chemical bonds such as carbon–carbon bonds and ether bonds. Degradation is one of the ways to achieve the high-value conversion of lignin, among which the heating degradation of lignin by deep eutectic solvent (DES) can be an excellent green degradation method. In this study, choline chloride (CC) was used as the hydrogen bond acceptor, and urea (UR), ethylene glycol (GC), glycerol (GE), acetic acid (AA), methyl acetate mixed acid (MA), oxalic acid (OX), and p-toluenesulfonic acid (TA) were used as hydrogen bond donors to degrade lignin. NMR hydrogen spectroscopy was used for the simple and rapid determination of phenolic hydroxyl groups in lignin. FT-IR spectroscopy was used to characterize the changes of functional groups of lignin during DES treatment. GPC observed the molecular weight of lignin after degradation and found a significant increase in the homogeneity (1.6–2.0) and a significant decrease in the molecular weight Mw (2478–4330) of the regenerated lignin. It was found that acidic DES was more effective in depolymerizing alkaline lignin, especially for the toluene–choline chloride. Seven DES solutions were recovered, and it was found that the recovery of DES still reached more than 80% at the first recovery.

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Section: Resultsmentioning

confidence: 99%

Comparison of the Degradation Performance of Seven Different Choline Chloride-Based DES Systems on Alkaline Lignin

et al. 2022

Polymers

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“…Various DES-like mixtures [30] were tested in this work to dissolve alkaline lignin, and a microscope, FT-IR, and NMR were used for subsequent analysis of the lignin composition.…”

Section: The Effect Of Des-like Mixtures On Model Samples and Machine...mentioning

confidence: 99%

“…When using DES-like mixtures based on choline chloride/lactic acid for the extraction of lignin from softwood, a higher lignin extraction (56.7-77.7%) was achieved than when extracting lignin from brewer's draff (34.5-39.3%), which may be due to the difference in % lignin in the input biomass, the complexity of the structure of lignin, or the different presence of lignin subunits (G, H, and S). Furthermore, the results revealed that acidic DES-like mixtures with a carboxylic acid, such as HBDs (lactic acid; pK a = 3.08), achieved a higher extraction efficiency than another type of HBD (glycerol; pK a = 14.15) [30]. FT-IR images revealed that DES-like mixtures based on choline chloride/lactic acid were able to extract lignin from biomass but did not cause adverse reactions by forming esters by binding through phenolic hydroxyl groups of lignin subunits by grafting.…”

Section: Fractionation Of Lignocellulosic Materials Using Des-like Mi...mentioning

confidence: 99%

“…The addition of lignin value is provided by the pretreatment of lignocellulosic materials, but it is challenging to achieve an intact lignin structure during the fractionation or delignification process. Liu et al [30] reported that if choline chloride is used as an HBA and lactic acid is used as an HBD, this system can initiate H-bonding, polarity, π-π, and ionic or charge interactions with lignin. Lactic acid can further promote the hydrolysis of hemicelluloses and thus the extraction of lignin.…”

Section: Properties Of Des-like Mixtures and Their Influence In Ligni...mentioning

confidence: 99%

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Exploiting Deep Eutectic Solvent-like Mixtures for Fractionation Biomass, and the Mechanism Removal of Lignin: A Review

Jančíková,

Jablonský

2024

Sustainability

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Green solvents, which include deep eutectic solvent-like mixtures (DES-like mixtures), are categorized as ecological and economical solvents for the pretreatment and fractionation of different types of biomasses. DES-like mixtures represent a group of the most promising green solvents for lignocellulosic pretreatment and are currently used effectively in the biomass pretreatment process. The present work describes the latest applications of DES-like mixtures in biomass delignification processes and, at the same time, summarizes the mechanism of action and influence of DES-like mixture systems on the removal of lignin from different types of biomasses. The results of this review indicate that the physicochemical properties (acidity, hydrogen bond capacity, polarity, viscosity, and water content) of DES-like mixtures have a significant effect on the biomass fractionation process. In addition to the nature of components forming DES-like mixtures, the reaction conditions (temperature, time) influence the efficiency of delignification. Active protons obtained from the hydrogen bond donor facilitate proton-catalyzed bond cleavage during fractionation, where the most significant step is the destruction of the ether and ester bonds between polysaccharides and lignin. DES-like mixtures can depolymerize lignin with subsequent breakdown of the β−O−4 bonds.

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“…Hal tersebut dapat terjadi karena lignin merupakan komponen yang sangat sulit didekomposisi, baik dengan perlakuan fisik seperti pemanasan, atau dengan perlakuan lain seperti fermentasi. Liu et al (2020) menyatakan bahwa lignin merupakan salah satu dari tiga komponen utama lignoselulosa yang terkondensasi stabil, sehingga sulit untuk dihancurkan dengan perlakuan suhu yang tinggi atau gelombang mikro. Kadar lignin pada bekatul gandum pada lama pemanasan 15 menit sebesar 0,8-0,11%, dan pada lama pemanasan 30 menit sebesar 0,5-0,7%.…”

Section: Profil Serat Bekatul Gandumunclassified

Kualitas Kimia dan Profil Serat Bekatul Gandum dengan Kadar Air dan Lama Pemanasan Berbeda

Utama

Sulistiyanto

Barus

et al. 2022

J. Apl. Teknol. Pang.

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Bekatul gandum (wheat pollard) merupakan hasil samping industri pengolahan gandum yang makin banyak digunakan untuk bahan makanan dan kualitasnya sangat tergantung pada kadar air dan lama pemanasan. Penelitian bertujuan mengkaji pengaruh kadar air dan lama pemanasan yang berbeda terhadap kualitas kimia dan profil serat bekatul gandum. Penelitian menggunakan Rancangan Acak Lengkap faktorial 3 × 2 dengan 3 ulangan. Faktor pertama adalah kadar air 12, 30, dan 60%. Faktor kedua adalah lama pemanasan 15 dan 30 menit. Kandungan kimia berupa kadar air, abu, lemak kasar, protein kasar, serat kasar, bahan ekstrak tanpa nitrogen (BETN) dan gross energy dianalisis dalam penelitian ini. Demikian juga profil serat (kadar Acid Detergent Fiber (ADF), Neutral Detergent Fiber (NDF), hemiselulosa, selulosa dan lignin.) serta profil serat melalui Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX). Hasil penelitian menunjukkan bahwa tidak ada pengaruh perlakuan kadar air dan pemanasan terhadap kandungan kimia, profil serat bekatul gandum dan profil serat melalui SEM-EDX. Kesimpulan penelitian adalah kadar air dan lama pemanasan tidak menentukan kualitas kimia dan profil serat pada bekatul gandum.Chemical Quality and Fiber Profile Wheat Pollard with Different Water Content and Steaming Durration AbstractWheat bran has known as by product of wheat production which is recently used as food ingredient and its quality could be rely on the water content and heat temperature. The aim of the study was to examine the effect of water content and steaming durration on the chemical quality and fiber profile of wheat bran. The study used a factorial 3 × 2 Completely Randomized Design with 3 replications. The first factor was the water content of 12, 30, and 60%. The second factor was the heating time of 15 and 30 minutes. Moisture content, ash, crude fat, crude protein, crude fiber, nitrogen-free extract material (NFE) and gross energy), fiber profile (Acid Detergent Fiber (ADF) content, Neutral Detergent Fiber (NDF), hemicellulose, cellulose, and lignin.) were analyzed as well as fiber profiles through Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX). The results showed that no remarkable effect of treatment was detected on chemical content, wheat bran fiber profile and fiber profile through SEM-EDX. As conclusion, the water content and heating time did not affect the chemical quality and fiber profile of wheat bran.

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Possible dissolution mechanism of alkali lignin in lactic acid-choline chloride under mild conditions

Abstract: In this study, several representative deep eutectic solvents (DESs) were designed to evaluate the solubility for alkali lignin (AL).

Cited by 16 publications

References 27 publications

Comparison of the Degradation Performance of Seven Different Choline Chloride-Based DES Systems on Alkaline Lignin

Comparison of the Degradation Performance of Seven Different Choline Chloride-Based DES Systems on Alkaline Lignin

Exploiting Deep Eutectic Solvent-like Mixtures for Fractionation Biomass, and the Mechanism Removal of Lignin: A Review

Kualitas Kimia dan Profil Serat Bekatul Gandum dengan Kadar Air dan Lama Pemanasan Berbeda

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