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Arthur J Ragauskas - One of the best experts on this subject based on the ideXlab platform.

  • Insights of ethanol Organosolv pretreatment on Lignin properties of Broussonetia papyrifera.
    ACS Sustainable Chemistry & Engineering, 2018
    Co-Authors: Lan Yao, Arthur J Ragauskas, Chang Geun Yoo, Xianzhi Meng, Congxin Chen, Chengyu Dong, Haitao Yang
    Abstract:

    Delignification of Broussonetia papyrifera during ethanol Organosolv pretreatment was studied. Milled wood Lignin (MWL), the ethanol Organosolv Lignin recovered at 5 min (PL5), 10 min (PL10), and 60 min (PL60) during the pretreatment, and the residual Lignin (RL60) after the pretreatment were characterized and compared. GPC results demonstrated that the weight-average molecular weights (Mw) of the ethanol Organosolv Lignin fractions increased as the pretreatment time extended from 5 to 60 min. 31P NMR analysis revealed that the content of aliphatic OH decreased in the following order: RL60 < PL60 < PL5 < PL10 < MWL. HSQC NMR results suggested that the contents of syringyl, guaiacyl, p-hydroxybenzoate unit, phenylcoumaran, and resinol in the solubilized Lignin fractions were significantly changed during the pretreatment. In addition, a significant portion of β-O-4 interunit linkages of Lignin was cleaved during the pretreatment, leading to the formation of stilbene structures in Lignin samples such as PL60.

  • fractionation of Organosolv Lignin using acetone water and properties of the obtained fractions
    ACS Sustainable Chemistry & Engineering, 2017
    Co-Authors: Hasan Sadeghifar, Tyrone Wells, Fatemeh Sadeghifar, Joshua S Yuan, Arthur J Ragauskas
    Abstract:

    Lignin fractions with different molecular weight were prepared using a simple and almost green method from switchgrass and pine Organosolv Lignin. Different proportions of acetone in water, ranging from 30 to 60%, were used for Lignin fractionation. A higher concentration of acetone dissolved higher molecular weight fractions of the Lignin. Fractionated Organosolv Lignin showed different molecular weight and functional groups. Higher molecular weight fractions exhibited more aliphatic and less phenolic OH than lower molecular weight fractions. Lower molecular weight fractions lead to more homogeneous structure compared to samples with a higher molecular weight. All fractions showed strong antioxidant activity.

  • Effects of Organosolv and ammonia pretreatments on Lignin properties and its inhibition for enzymatic hydrolysis
    Green Chemistry, 2017
    Co-Authors: Chang Geun Yoo, Xianzhi Meng, Arthur J Ragauskas
    Abstract:

    Lignin offers structural support and protection for plant cell walls; however, it also contributes to biomass recalcitrance and the costs of biofuel production via the biological pathway. Organosolv and ammonia pretreatments have been developed to reduce biomass recalcitrance and improve sugar release performance during enzymatic hydrolysis. It is believed that Lignin properties are related to its inhibition on enzymatic hydrolysis; therefore, understanding the characteristics of Lignin is a key for effective biomass conversion to biofuels. In this study, an Organosolv pretreatment using 60% ethanol with 1.25% H2SO4 significantly deconstructed poplar Lignin and reduced its molecular weights due to the cleavage of Lignin inter-unit linkages. The Organosolv pretreatment increased the contents of phenolic OH units and the Lignin residue showed a high cellulase maximum adsorption capacity. Ammonia pretreatment with 5% ammonium hydroxide was not as effective as Organosolv pretreatment on Lignin deconstruction. Organosolv Lignin residue had lower Lignin S/G ratio than the untreated one. Compared to the Organosolv Lignin residue and untreated Lignin, ammonia Lignin residue had a higher cellulase adsorption affinity. In addition, the effects of Lignin on cellulose hydrolysis was investigated and the results suggested that the presence of Lignin with cellulose substrates reduced cellulose hydrolysis, and its inhibitory effect was primarily determined by the Lignin properties after each pretreatment. The Organosolv pretreatment resulted in a slightly lower cellulase binding strength (249.7 mL g−1) on poplar Lignin than that on untreated samples (261.1 mL g−1), while ammonia Lignin residue showed a higher cellulase binding strength (402.8 mL g−1) and had more significant inhibition effect on cellulose hydrolysis. These results demonstrated that the binding strength significantly affected the Lignin-derived inhibition on enzymatic hydrolysis of cellulose in the cellulose-Lignin mixtures.

  • physicochemical characterization of ethanol Organosolv Lignin eol from eucalyptus globulus effect of extraction conditions on the molecular structure
    Polymer Degradation and Stability, 2014
    Co-Authors: Mauricio Yanezs, Poulomi Sannigrahi, Betty Matsuhiro, Carolina Nunez, Shaobo Pan, Christopher A Hubbell, Arthur J Ragauskas
    Abstract:

    Abstract The aim of the present study was to investigate the effect of extraction conditions, mainly severity factor (H-factor = 3980–14,500) on the molecular structure of ethanol Organosolv Lignins extracted from Eucalyptus globulus . Isolated Lignins were structurally characterized by 1 H NMR, 31 P NMR, UV–Vis, FT-IR spectroscopy and gel permeation chromatography. The results showed that an increase in the severity of the pretreatment decreased the molecular weight of the Lignins within a 36–56% range with respect to the untreated Lignin (MWL). Moreover, the increase in severity of the Organosolv treatment was accompanied by strong decrease in the content of aliphatic hydroxyl groups and by an increase of syringyl phenolic units and condensed phenolic structures. The condensed phenolic structures quantified in the Organosolv Lignin correspond to resinol, phenylcoumaran, dibenzodioxocin, spirodienone and β-1′ linkages.

  • ethanol Organosolv Lignin based rigid polyurethane foam reinforced with cellulose nanowhiskers
    RSC Advances, 2012
    Co-Authors: Arthur J Ragauskas
    Abstract:

    An ethanol Organosolv Lignin polyol, prepared by reacting Lignin with propylene oxide catalyzed by potassium hydroxide, was used to synthesize rigid polyurethane foam which was further reinforced by cellulose nanowhiskers (CNWs) up to 5 wt%. The resulting nanocomposites have shown significantly improved mechanical and thermal properties primarily attributed to the phenolic structure and high functionality of Lignin as well as the rigidity of CNWs and crosslinking introduced by CNWs.

Nicolas Brosse - One of the best experts on this subject based on the ideXlab platform.

  • the capability of ultrafiltrated alkaline and Organosolv oil palm elaeis guineensis fronds Lignin as green corrosion inhibitor for mild steel in 0 5 m hcl solution
    Measurement, 2016
    Co-Authors: Afidah Abdul Rahim, Mohamad Nasir Mohamad Ibrahim, Hazwan M Hussin, Nicolas Brosse
    Abstract:

    Abstract The inhibitive effect of ultrafiltrated oil palm fronds (OPF) Lignins on the corrosion of mild steel in 0.5 M HCl solution has been investigated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP) and weight loss measurement. The presence of smaller Lignin fractions reduces remarkably the corrosion rate of mild steel. The highest corrosion inhibition efficiency for all ultrafiltrated Lignins were attained at maximum concentration of 500 ppm ( IE P.Soda : 87% >  IE P.Organosolv : 83% >  IE P.Kraft : 81%). The results from this corrosion test clearly reveal that all ultrafiltrated Lignins behaved as a mixed-type inhibitor with predominant anodic (Organosolv Lignin) or cathodic (alkaline Lignin) effectiveness. It was deduced that the inhibition process was spontaneous and the inhibitors were mainly physically adsorbed onto the mild steel surface.

  • Improved corrosion inhibition of mild steel by chemically modified Lignin polymers from Elaeis guineensis agricultural waste
    Materials Chemistry and Physics, 2015
    Co-Authors: M. Hazwan Hussin, Afidah Abdul Rahim, Mohamad Nasir Mohamad Ibrahim, Nicolas Brosse
    Abstract:

    This article describes that the modification of Lignin by incorporation of aromatic scavengers (2-naphthol: AHN EOL and 1,8-dihydroxyanthraquinone: AHD EOL) during delignification process has improved the physical properties of the Lignin fractions. Smaller fragments of Lignin with high phenolic -OH content, increased solubility and antioxidant activity have led to improved inhibitive property of the modified Lignin. The inhibition efficiency (84-93%) of both modified Lignin (500 ppm) were observed to be better than unmodified Organosolv Lignin (EOL). It was deduced that the inhibition process was spontaneous and the inhibitors were mainly physically adsorbed onto the mild steel surface.

  • extraction characterization and utilization of Organosolv miscanthus Lignin for the conception of environmentally friendly mixed tannin Lignin wood resins
    Journal of Adhesion Science and Technology, 2011
    Co-Authors: Roland El Hage, Nicolas Brosse, P Navarrete, A Pizzi
    Abstract:

    Lignin was extracted from Miscanthus × giganteus using two procedures: an aqueous-ethanol Organosolv treatment and a two-step process involving a dilute acid pre-soaking step followed by an aqueous-ethanol Organosolv treatment. The Organosolv Lignin was subjected to a comprehensive structural characterization by 13C and MALDI-TOF MS and used for the formulation of a green wood adhesive prepared with 100% natural resins. The best formulation was composed of 60% of mimosa tannin and 40% of glyoxalated Lignin extracted using a 1-step Organosolv treatment. This formulation, when applied to wooden test panels yielded good internal bond strength results, which was good enough to pass relevant international standard specifications for interior-grade panels.

  • effects of process severity on the chemical structure of miscanthus ethanol Organosolv Lignin
    Polymer Degradation and Stability, 2010
    Co-Authors: Roland El Hage, Poulomi Sannigrahi, Nicolas Brosse, Arthur J Ragauskas
    Abstract:

    Abstract Ethanol Organosolv Lignin extracted from Miscanthus × giganteus with differing levels of severity (1.75  13 C, 31 P NMR, FTIR spectroscopy and gel permeation chromatography. The results were compared to those from milled wood Lignin from the same feedstock. The results showed that an increase in the severity of the treatment enhanced the dehydration reactions on the side chain and the condensation of Lignin, increased the concentration of phenol groups and decreased the molecular mass of Lignin fragments. It appeared that for the experimental conditions generally employed the cleavage of α-aryl ether bonds is primarily reaction responsible for Lignin depolymerization under the Organosolv conditions examined.

  • characterization of milled wood Lignin and ethanol Organosolv Lignin from miscanthus
    Polymer Degradation and Stability, 2009
    Co-Authors: Roland El Hage, Nicolas Brosse, Poulomi Sannigrahi, Laurent Chrusciel, Christian Sanchez, Arthur J Ragauskas
    Abstract:

    Abstract Ethanol Organosolv Lignin extracted from Miscanthus  ×  giganteus (using the following conditions: T  = 190 °C, t  = 60 min, sulfuric acid = 1.2% w/w, EtOH/H 2 O = 0.65) and milled wood Lignin from Miscanthus  ×  giganteus were subjected to a comprehensive structural characterization by 13 C, 31 P NMR, FTIR, UV spectroscopies and size exclusion chromatography. The results showed that Miscanthus Lignin is an H/G/S type (4%, 52%, 44% respectively) with ∼0.41 β-O-4 linkage per aromatic ring and contains coumarylate linkages (0.1/Ar). It was shown that during Organosolv treatment, cleavage of β-O-4 linkages and of ester bond (acetyl and coumaryl residues) was the major mechanisms of Lignin breakdown but the process did not significantly change the core of the Lignin structure.

Ingyu Choi - One of the best experts on this subject based on the ideXlab platform.

Ning Yan - One of the best experts on this subject based on the ideXlab platform.

  • base promoted hydrogenolysis of Lignin model compounds and Organosolv Lignin over metal catalysts in water
    Chemical Engineering Science, 2015
    Co-Authors: Jiaguang Zhang, Hannelore Konnerth, Martin H G Prechtl, Ning Yan
    Abstract:

    Herein we present a systematic investigation on the promotional effect of base in metal catalysed hydrogenolysis of Lignin model compounds and Organosolv Lignin. The research started with the evaluation of pH effects (pH 1–14) on the hydrogenolysis of a Lignin β-O-4 model compound over a Ru catalyst (a stable catalyst over a wide pH range), from which a significantly increased selectivity towards monomeric compounds was observed in the presence of base. This promotional effect was studied in detail over bimetallic Ni7Au3 nanoparticles. Addition of a strong base such as NaOH significantly enhanced the activity and selectivity for C-O bond hydrogenolysis over undesired hydrogenation reactions, not only in Lignin model compounds but also in real Lignin conversion. Notably, the yield for monomeric aromatic compounds from Lignin over Ni7Au3 catalyst increased ca. 100% after adding NaOH as a promoter, under the same reaction conditions. Mechanistic study suggest that addition of base significantly reduced the benzene ring hydrogenation activity of the metal catalysts. The effect of adding different bases over various metal catalysts were also investigated.

  • highly efficient niau catalyzed hydrogenolysis of Lignin into phenolic chemicals
    Green Chemistry, 2014
    Co-Authors: Jiaguang Zhang, Hiroyuki Asakura, Jeaphianne Van Rijn, Jun Yang, Paul N Duchesne, Bin Zhang, Xi Chen, Peng Zhang, Mark Saeys, Ning Yan
    Abstract:

    A highly efficient, stable NiAu catalyst that exhibits unprecedented low temperature activity in Lignin hydrogenolysis was for the first time developed, leading to the formation of 14 wt% aromatic monomers from Organosolv Lignin at 170 °C in pure water.

Jalel Labidi - One of the best experts on this subject based on the ideXlab platform.

  • base catalyzed depolymerization of Lignin influence of Organosolv Lignin nature
    Biomass & Bioenergy, 2014
    Co-Authors: Xabier Erdocia, Raquel Prado, Angeles M Corcuera, Jalel Labidi
    Abstract:

    Abstract Three different Lignins obtained from olive tree pruning by Organosolv processes (acetosolv, formosolv and acetosolv/formosolv) were depolymerized by alkaline hydrolysis in a batch reactor to produce high value added compounds. Obtained products (oil, coke, residual Lignin and gas) were measured and analyzed determining their composition and yield in order to study the changes of the depolymerization process for different Organosolv Lignin samples. For this purpose, different analytical methods were used (gas chromatography/mass spectroscopy, high performance size exclusion chromatography, pyrolysis–GC–MS, MALDI-TOF). Acetosolv Lignin and acetosolv/formosolv Lignin gave the highest yield of desired product with 18.48 and 16.25% of oil yield respectively. However, formosolv Lignin had the highest proportion of monomeric phenolic compounds in the oil (28.19%). Catechol and its derivatives were the main products in all studied cases, but they were more abundant in the case of formosolv Lignin depolymerization. Otherwise, the residual Lignin formed during the repolymerization process was the same in both, yield and nature, for all cases.

  • Organosolv Lignin depolymerization with different base catalysts
    Journal of Chemical Technology & Biotechnology, 2012
    Co-Authors: Ana Toledano, Luis Serrano, Jalel Labidi
    Abstract:

    BACKGROUND: Revalorization of Lignin is one of the key economical requirements for the development of cost-effective biorefinery processes. The Lignin polyphenolic structure is ideally suited to transformation catalytically into lower molecular weight compounds such as phenols, aromatic acids, esters, ethers, etc., replacing those obtained from petroleum. RESULTS: Lignin was subjected to base catalyzed depolymerization paying attention to the base effect on the oil yield and composition. The oil yields and compositions varied (5–20%) strongly depending on the base used, suggesting that the reactions took place via different mechanisms. As a result, the monomeric compounds obtained were different (catechol, cresols, syringol, guaiacol). Residual Lignin contents were high for most of the experiments (up to 45%), and repolymerization reactions were proved to be one of the main reasons for this behavior. CONCLUSION: The results showed that Lignin depolymerization produced phenolic compounds that can be introduced into existing petrochemical industries. The base selection will govern the nature of the products obtained. Repolymerization was proved to take place and to be the reason for the limitation on oil production. Copyright © 2012 Society of Chemical Industry