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  • 51.
    Li, Jiebing
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Gellerstedt, Göran
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Toven, Kai
    Elucidation and Quantification of Pseudolignin Structures Formed during Steam Explosion2008In: PROCEEDINGS OF INTERNATIONAL CONFERENCE ON PULPING, PAPERMAKING AND BIOTECHNOLOGY 2008: ICPPB '08, VOL I / [ed] Jin Y; Zhai H; Li Z, NANJING: NANJING FORESTRY UNIV , 2008, p. 631-636Conference paper (Refereed)
    Abstract [en]

    Structural characterization of the lignin obtained in a biomass-to-ethanol process is of importance for the lignin utilization which is in turn economically critical for the process. For steam explosion lignins, it has been found that there is a noticeable amount of pseudolignin structures present, appearing as two unique peaks in 2D HSQC NMR. The structures were elucidated as the condensed structures between lignin with furfural and with hydroxymethyl furfural (HMF) via a double bond connection. All isolated steam explosion lignins contain the structures in a quantity of 1 to 4 furan nuclei per 100 lignin C6 units.

  • 52.
    Li, Jiebing
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Gellerstedt, Göran
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Toven, Kai
    Steam explosion lignins; their extraction, structure and potential as feedstock for biodiesel and chemicals2009In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 100, no 9, p. 2556-2561Article in journal (Refereed)
    Abstract [en]

    In the present study, a steam explosion wood pre-treatment process, optimized earlier with respect to ethanol production, has been applied to both softwoods (Picea abies and Pinus sylvestris) and hardwoods (Betula verrucosa and Populus tremula). The alkaline extractable lignins have then been isolated to investigate lignin separation efficiency and lignin structure and to evaluate their potential for producing value-added products, such as biodiesel components or chemicals, in terms of the purity, molecular size, functional groups, beta-O-4' inter-unit linkage content, and degradability in a subsequent processing treatment. The mechanism of lignin modification and possible improvements to the steam explosion pre-treatment process are discussed.

  • 53.
    Li, Jiebing
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Henriksson, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Gellerstedt, Göran
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Carbohydrate reactions during high-temperature steam treatment of aspen wood2005In: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1559-0291, Vol. 125, no 3, p. 175-188Article in journal (Refereed)
    Abstract [en]

    Aspen wood was treated with steam at different time-temperature severity factors. Analysis of the amounts of acids released revealed a relationship between the acidity and the formation of furfural and hydroxymethyl furfural as degradation products from carbohydrates. It is suggested that two concurrent or consecutive mechanisms are responsible for the observed results: a homolytic cleavage and an acid hydrolysis of glucosidic linkages in the polysaccharides. By preimpregnating the wood with alkali, hydrolysis can be eliminated, resulting in a much cleaner depolymerization of the polysaccharides without any further acid-catalyzed degradation. The enzymatic digestibility of the steam-treated wood material for the formation of glucose was compared with that of steam-exploded wood. A more efficient route for glucose production from steam-exploded wood was found as long as the biomass-pretreated material was homogeneous and without shives.

  • 54.
    Li, Jiebing
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Henriksson, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Gellerstedt, Göran
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Lignin depolymerization/repolymerization and its critical role for delignification of aspen wood by steam explosion2007In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 98, no 16, p. 3061-3068Article in journal (Refereed)
    Abstract [en]

    Steam explosion is an important process for the fractionation of biomass components. In order to understand the behaviour of lignin under the conditions encountered in the steam explosion process, as well as in other types of steam treatment, aspen wood and isolated lignin from aspen were subjected to steam treatment under various conditions. The lignin portion was analyzed using NMR and size exclusion chromatography as major analytical techniques. Thereby, the competition between lignin depolymerization and repolymerization was revealed and the conditions required for these two types of reaction identified. Addition of a reactive phenol, 2-naphthol, was shown to inhibit the repolymerization reaction strongly, resulting in a highly improved delignification by subsequent solvent extraction and an extracted lignin of uniform structure.

  • 55.
    Li, Jiebing
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Kisara, Koki
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Danielsson, Sverker
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Lindström, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Gellerstedt, Göran
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    An improved methodology for the quantification of uronic acid units in xylans and other polysaccharides2007In: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 342, no 11, p. 1442-1449Article in journal (Refereed)
    Abstract [en]

    Uronic acids can be quantified either by a colorimetric determination after treatment with concentrated sulfuric acid and carbazole or by gas chromatography after methanolysis and subsequent acetylation. Both methods suffer from incomplete hydrolysis, an unavoidable degradation of the products to be analysed, and an inability to separate and quantify different types of uronic acids. In the present work, the fundamental chemistry involved in the two methods has been evaluated, and some modifications to increase their accuracy are suggested. By combining the two methods, a complete quantification of all individual types of urome acids present in a sample can be achieved.

  • 56.
    Li, Jiebing
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Lindström, Mikael E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    An HPLC method for pentosans quantification in biomass, pulp and other biomass product2008Conference paper (Refereed)
  • 57.
    Li, Jiebing
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Martin-Sampedro, Raquel
    Pedrazzi, Cristiane
    Gellerstedt, Göran
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Fractionation and characterization of lignin-carbohydrate complexes (LCCs) from eucalyptus fibers2011In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 65, no 1, p. 43-50Article in journal (Refereed)
    Abstract [en]

    The effect of milling time on the structure of lignin was investigated by analyzing the quantity and molecular size distribution of thioacidolysis products obtained from wood and pulp of eucalypt (Eucalyptus globulus). After milling, the ability of three solvent systems was determined to completely dissolve the wood or pulp meal. It was found that a mixture of DMSO and 50% aqueous tetrabutylammonium hydroxide was superior to either dimethylacetamide-LiCl or DMSO-tetrabutylammonium fluoride as solvent. By applying the minimum milling time required for complete dissolution, structurally unaltered wood or pulp could be further separated into lignin-carbohydrate fractions. These were analyzed by thioacidolysis. From eucalypt pulp, two different lignin-carbohydrate fractions were obtained, one glucan-and one xylan-enriched fraction, with the latter having more syringyl units in its lignin moieties. The developed solvent system seems to be universal because spruce and flax fibers and pulps could also be dissolved in it after milling.

  • 58.
    Li, Jiebing
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Martin-Sampedro, Raquel
    National Institute for Agriculture and Food Research and Technology, INIA, Madrid, Spain.
    Pedrazzi, Cristiane
    Pulp and Paper Laboratory, Federal University of Vicosa, Brazil.
    Henriksson, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Gellerstedt, Göran
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Fractionation and characterization of lignin–carbohydrate complexes (LCCs) from eucalyptus fibers2009Conference paper (Refereed)
  • 59.
    Li, Jiebing
    et al.
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    Sevastyanova, Olena
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    Gellerstedt, Göran
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    The distribution of oxidizable structures in ECF- and TCF- bleached kraft pulps2002In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 17, no 4, p. 415-419Article in journal (Refereed)
    Abstract [en]

    The kappa number in kraft pulp contains contributions from lignin and from other oxidizable structures denoted as false lignin. The latter can be divided in hexenuronic acid groups and "non-lignin" structures. In this paper, the kappa number units due to the various contributing structures have been quantified by fractionation of the kappa number. Bleached spruce and birch kraft industrial pulps taken after each stage in an ECF (ODEQP) and in a TCF (OQOPQPO) bleaching sequence respectively have been assessed. Possible correlations between the content of false lignin, the pulp origin, the bleaching conditions, and brightness and viscosity values have been sought. It is concluded that the false lignin structures are formed predominantly during the cooking and oxygen delignification stages. The false lignin structures were found to give different responses in the various bleaching stages, but to have no influence on either pulp brightness or viscosity.

  • 60.
    Li, Jiebing
    et al.
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    Sevastyanova, Olena
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    Gellerstedt, Göran
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    The relationship between kappa number and oxidizable structures in bleached kraft pulps2002In: Journal of Pulp and Paper Science (JPPS), ISSN 0826-6220, Vol. 28, no 8, p. 262-266Article in journal (Refereed)
    Abstract [en]

    The relationship between residual oxidized lignin structures in spruce and birch kraft pulps and their kappa number contribution after each stage in an ODEQP (spruce) and an OQ(OP)Q(PO) (birch) sequence, respectively, has been investigated. Analysis by a modified kappa number method (OxDem kappa number) as well as by determination of permanganate oxidation equivalents on various isolated residual lignin samples revealed that the relationship between the lignin content and kappa number gradually changes as the bleaching sequence proceeds, giving values that differ substantially from that found in unbleached kraft pulp. These effects can be attributed to the successive oxidative fragmentation of aromatic rings and the formation of carboxyl and non-aromatic unsaturated structures in the residual lignin structure. Therefore, a kappa number determination on pulp which has been subjected to an oxidative stage will result in an underestimation of the lignin content.

  • 61.
    Li, Jiebing
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Shi, Chao
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Lindström, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Henriksson, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    The methoxy group of beta-O-methyl glucuronic acid is central for the formation of hexenuronic acid during kraft pulping2011In: O Papel, ISSN 0031-1057, Vol. 72, no 1, p. 54-65Article in journal (Refereed)
    Abstract [en]

    Hexenuronic acid is created from 4-O-methyl gluc-uronic acid – a side chain group in xylan, and one of the most important hemicelluloses in both hardwood and softwood - during alkaline conditions, such as kraft pulping. Especially in hardwood kraft pulp, hexenuronic acid corresponds to a large part of the kappa number, and the presence of this component in bleached pulp causes post yellowing. In this work it is shown that glucuronic acid that lacks a methoxy group on the 4-carbon does not form hexenuronic acid under alkaline condition to the same extent as 4-O-methylglucuronic acid. This opens up novel strategies for genetic modification of the hemicellulose structures in wood cultivated for kraft pulping.

  • 62.
    Li, Jiebing
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Wang, Miao
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    She, Diao
    Zhao, Yadong
    Structural functionalization of industrial softwood kraft lignin for simple dip-coating of urea as highly efficient nitrogen fertilizerIn: Article in journal (Refereed)
    Abstract [en]

    Urea coating was conducted using polylactic acid (PLA) blended with industrial softwood kraft lignin after applying a dip-coating technique. The lignin was pre-functionalized via esterification that increased coat layer hydrophobicity or via amination that created an organically bound nitrogen structure. The PLA film reference had many pores, while the film from the PLA-lignin derivative complex was highly homogeneous and had no pores. The coat thickness was generally adjustable by repeating the coating process reaching up to 81% weight against the urea core. After coating, urea release in water was largely delayed, 20-30 and 6-10 times as long as that of uncoated urea or PLA-coated urea respectively. The coated urea will be a highly effective nitrogen fertilizer due to the controlled release after coating, the slow release from the organically bound nitrogen structure, and the expectedly extra stability against urease hydrolysis and microorganism nitrification after using the lignin structure.

  • 63.
    Li, Jiebing
    et al.
    KTH. Research Institutes of Sweden RISE, Drottning Kristinas väg 61, 11486 Stockholm, Sweden.
    Wang, Miao
    KTH. Research Institutes of Sweden RISE, Drottning Kristinas väg 61, 11486 Stockholm, Sweden.
    She, Diao
    Zhao, Yadong
    KTH.
    Structural functionalization of industrial softwood kraft lignin for simple dip-coating of urea as highly efficient nitrogen fertilizer2017In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 109, p. 255-265Article in journal (Refereed)
    Abstract [en]

    Urea coating was conducted using polylactic acid (PLA) blended with industrial softwood kraft lignin after applying a dip-coating technique. The lignin was pre-functionalized via esterification that increased coat layer hydrophobicity or via amination that created an organically bound nitrogen structure. The PLA film reference had many pores, while the film from the PLA-lignin derivative complex was highly homogeneous and had no pores. The coat thickness was generally adjustable by repeating the coating process reaching up to 81% weight against the urea core. After coating, urea release in water was largely delayed, 20-30 and 6-10 times as long as that of uncoated urea or PLA-coated urea respectively. The coated urea will be a highly effective nitrogen fertilizer due to the controlled release after coating, the slow release from the organically bound nitrogen structure, and the expectedly extra stability against urease hydrolysis and microorganism nitrification after using the lignin structure.

  • 64.
    Li, Jiebing
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Zhao, Yadong
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Bouquet, Jean-Marie
    Magnesen, Thorolf
    Thompson, Eric M.
    Troedsson, Christofer
    Chemical composition of Ciona intestinalis under different aquaculture conditions and from different body fractionManuscript (preprint) (Other academic)
  • 65.
    Lima, Raquel B.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Raza, Rizwan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Qin, Haiying
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Fan, Liangdong
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Direct lignin fuel cell for power generation2011In: 16th International Symposium on Wood, Fiber and Pulping Chemistry: Proceedings, ISWFPC, 2011, p. 257-262Conference paper (Refereed)
    Abstract [en]

    Lignin, the second most abundant component after cellulose in biomass, has been examined in this study as a fuel for a direct conversion into electricity using direct carbon fuel cell (DCFC). Two different types of industrial lignins were investigated: lignosulphonate (LS) and kraft lignin (KL), either directly in their commercial forms, after their blending with commercial active carbon (AC) or after alternation of their structures by a pH adjustment to pH 10. It has been found that the open circuit voltage (OCV) of the DCFC could reach around 0.7 V in most of the trials. Addition of active carbon increased the maximum current density from 43∼57 to 85∼101 mA/cm 2. The pH adjustment not only increased the maximum current density but also reduced the differences between the two types of lignins, resulting in an OCV of 0.680-0.699 V and a maximum current density of 74∼79 mA/cm 2 from both lignins. Typical power density was 12 (for KL +AC) and 24 mW cm -2 (for LS +AC). It has been concluded that a direct lignin fuel cell is feasible and the lignin hydrophilicity is critical for the cell performance.

  • 66.
    Lima, Raquel Bohn
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Li, Jiebing
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Raza, Rizwan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Ceria-carbonates nanocomposite electrolyte for lignin based fuel cell2012In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 243Article in journal (Other academic)
  • 67.
    Lima, Raquel Bohn
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Raza, Rizwan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Qin, Haiying
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Direct lignin fuel cell for power generation2013In: RSC Advances, E-ISSN 2046-2069, Vol. 3, no 15, p. 5083-5089Article in journal (Refereed)
    Abstract [en]

    Lignin, the second most abundant component after cellulose in biomass, has been examined in this study as a fuel for direct conversion into electricity using direct carbon fuel cells (DCFC). Two different types of industrial lignins were investigated: Lignosulfonate (LS) and Kraft lignin (KL), in their commercial forms, after their blending with commercial active carbon (AC) or after alteration of their structures by a pH adjustment to pH 10. It was found that the open circuit voltage (OCV) of the DCFC could reach around 0.7 V in most of the trials. Addition of active carbon increased the maximum current density from 43-57 to 83-101 mA cm(-2). The pH adjustment not only increased the maximum current density but also reduced the differences between the two types of lignins, resulting in an OCV of 0.68-0.69 V and a maximum current density of 74-79 mA cm(-2) from both lignins. Typical power density was 12 (for KL + AC) and 24 mW cm(-2) (for LS + AC). It is concluded that a direct lignin fuel cell is feasible and the lignin hydrophilicity is critical for the cell performance.

  • 68.
    Lindström, Mikael E.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Shi, C.
    Henriksson, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    A genetic strategy for avoiding formation of hexenuronic acid in kraft pulping?2011Conference paper (Other academic)
  • 69. Martín, M. E. E.
    et al.
    Du, Xueyu
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Towards improvements of kraft pulp bleaching by additional treatments2011In: 16th International Symposium on Wood, Fiber and Pulping Chemistry: Proceedings, ISWFPC, 2011, p. 699-704Conference paper (Refereed)
    Abstract [en]

    During the last decade, many efforts have been made in pulp and paper industry to construct more effective, sustainable and environmentally friendly pulp bleaching sequences. In this work, enzymatic (laccase-mediator system, L), non-oxidative chemical (urea, U) and mechanical (PFI refining, R) treatments have been conducted, alone or in a combination, on unbleached eucalyptus kraft pulps to evaluate their bleaching effects and thus the further potential as additional treatment(s) on a conventional bleaching process. The pulps obtained were characterized in terms of kappa number, hexenuronic acid content, brightness and viscosity. Moreover, the lignin-carbohydrates complexes (LCCs) were fractionated and characterized concerning lignin content and carbohydrate composition and for 1HNMR and thioacidolysis-GC and -SEC analysis. It has been found that the effect of the L treatment was limited at delignification by a kappa number reduction of 0.8 units. The effects of the U treatment included delignification (1.4 kappa units), HexA removal (3 mol/g) and pulp brightening (3.4 ISO units). The refining darkened the pulp (3 ISO units) while the subsequent L or U treatment could bleached more than without the R stage. The delignification extent by all the treatments could be noticed also from the isolation yields of the LCC1 (glucan-lignin) fraction. Thioacidolysis-SEC analysis revealed the darkening mechanism of the R treatment and the delignification mechanisms of L and U treatment, showing that the L treatment removed more effectively the condensed parts of the lignin located at LCC2 (xylan-lignin) fraction.

  • 70.
    Moriana, Rosana
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Zhang, Yujia
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Mischnick, Petra
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Thermal degradation behavior and kinetic analysis of spruce glucomannan and its methylated derivatives2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 106, no 1, p. 60-70Article in journal (Refereed)
    Abstract [en]

    The thermal degradation behavior and kinetics of spruce glucomannan (SGM) and its methylated derivatives were investigated using thermogravimetric analysis to characterize its temperature-dependent changes for use in specific applications. The results were compared with those obtained for commercial konjac glucomannan (KGM). The SGM and the KGM exhibited two overlapping peaks from 200 to 375 C, which correspond to the intensive devolatilization of more than 59% of the total weight. Differences in the pyrolysis-product distributions and thermal stabilities appeared as a result of the different chemical compositions and molecular weights of the two GMs. The Friedman and Flynn-Wall-Ozawa isoconversional methods and the Coats-Redfern were adopted to determine the kinetic triplet of the intensive devolatilization region. Both GMs can be modeled using a complex mechanism that involves both a Dn-type and an Fn-type reaction. The comparative study of partially methylated GM indicated higher homogeneity and thermal resistance for the material with the higher degree of substitution.

  • 71. Prasetyo, Endry Nugroho
    et al.
    Kudanga, Tukayi
    Ostergaard, Lars
    Rencoret, Jorge
    Gutierrez, Ana
    del Rio, Jose C.
    Ignacio Santos, J.
    Nieto, Lidia
    Jimenez-Barbero, Jesus
    Martinez, Angel T.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Gellerstedt, Goran
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Lepifre, Stephane
    Silva, Carla
    Kim, Su Yeon
    Cavaco-Paulo, Artur
    Klausen, Bente Seljebakken
    Lutnaes, Bjart Frode
    Nyanhongo, Gibson S.
    Guebitz, Georg M.
    Polymerization of lignosulfonates by the laccase-HBT (1-hydroxybenzotriazole) system improves dispersibility2010In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 101, no 14, p. 5054-5062Article in journal (Refereed)
    Abstract [en]

    The ability of laccases from Trametes villosa (TvL), Myceliophthora thermophila (MtL), Trametes hirsuta (ThL) and Bacillus subtilis (BsL) to improve the dispersion properties of calcium lignosulfonates 398 in the presence of HBT as a mediator was investigated. Size exclusion chromatography showed an extensive increase in molecular weight of the samples incubated with TvL and ThL by 107% and 572% from 28400 Da after 17 h of incubation, respectively. Interestingly, FTIR spectroscopy. C-13 NMR and Py-GC/MS analysis of the treated samples suggested no substantial changes in the aromatic signal of the lignosulfonates, a good indication of the ability of TvL/ThL-HBT systems to limit their effect on functional groups without degrading the lignin backbone. Further, the enzymatic treatments led to a general increase in the dispersion properties, indeed a welcome development for its application in polymer blends. (C) 2010 Elsevier Ltd. All rights reserved.

  • 72. Rencoret, Jorge
    et al.
    Marques, Gisela
    Gutierrez, Ana
    Ibarra, David
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Gellerstedt, Göran
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Santos, J. Ignacio
    Jimenez-Barbero, Jesus
    Martinez, Angel T.
    del Rio, Jose C.
    Structural characterization of milled wood lignins from different eucalypt species2008In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 62, no 5, p. 514-526Article in journal (Refereed)
    Abstract [en]

    The chemical structure of milled-wood lignins from Eucalyptus globulus, E. nitens, E. maidenii, E. grandis, and E. dunnii was investigated. The lignins were characterized by analytical pyrolysis, thioacidolysis, and 2D-NMR that confirmed the predominance of syringyl over guaiacyl units and only showed traces of p-hydroxyphenyl units. E. globulus lignin had the highest syringyl content. The heteronuclear single quantum correlation (HSQC) NMR spectra yielded information about relative abundances of inter-unit linkages in the whole polymer. All the lignins showed a predominance of beta-O-4' ether linkages (66-72% of total side-chains), followed by beta-beta' resinol-type linkages (16-19%) and lower amounts of beta-5' phenylcoumarin-type (3-7%) and beta-1' spirodienone-type linkages (1-4%). The analysis of desulfurated thioacidolysis dimers provided additional information on the relative abundances of the various carbon-carbon and diaryl ether bonds, and the type of units ( syringyl or guaiacyl) involved in each of the above linkage types. Interestingly, 93-94% of the total beta-beta' dimers included two syringyl units indicating that most of the beta-beta' substructures identified in the HSQC spectra were of the syringaresinol type. Moreover, three isomers of a major trimeric compound were found which were tentatively identified as arising from a beta-beta' syringaresinol substructure attached to a guaiacyl unit through a 4-O-5' linkage.

  • 73.
    Sevastyanova, Olena B.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Gellerstedt, Göran L. F.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    On the reaction mechanism of thermal yellowing of chemical pulp2005In: Appita Annu. Conf., 2005, p. 517-523Conference paper (Refereed)
    Abstract [en]

    In the present research the mechanism of colour formation in the bleached kraft pulps was studied based on the accelerated ageing experiments with industrial bleached pulps and cellulose samples doped with a number of model compounds: 2-furancarboxylic acid (FA), 5-formyl-2-furancarboxylic acid (FFA) and reductic acid (RA) in combination with Fe2+ or Fe3+ ion. The choice of the model compounds was based on the fact that they were detected in the ethanol extracts of aged industrial pulps. It was shown that the mechanism of thermal yellowing consist of several stages, including the degradation of hexenuronic acid and formation of reactive precursors, such as FFA and RA, which then take part in reactions leading to colour formation. The formation of FFA and RA is the rate-limiting stage in the discoloration of pulps. FA had basically no influence on the yellowing. The effect of Fe ions on the colour formation appears to vary with their oxidation state. The presence of Fe2+ in combination of FFA, and especially, with RA has been shown to facilitate the colour formation, whereas Fe3+ seems to suppress the discoloration caused by the FFA or RA.

  • 74.
    Sevastyanova, Olena
    et al.
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    Gellerstedt, Göran
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    Extractability and chemical structure of residual and false lignin in kraft pulps2001Conference paper (Refereed)
  • 75.
    Sevastyanova, Olena
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Gellerstedt, Göran
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    On the reaction mechanism of the thermal yellowing of bleached chemical pulps2006In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 21, no 2, p. 188-192Article in journal (Refereed)
    Abstract [en]

    The mechanism of moist thermal yellowing of fully bleached chemical pulps was studied using dissolving pulp impregnated with different types of degradation products from hexenuronic acid, viz. 2-furancarboxylic acid, 5-formyl-2-furancarboxylic acid and 2,3-dihydroxy-2-cyclopenten-l-one (reductic acid) either alone or in combination with Fe2+ or Fe3+ ions. It was found that the two latter acids take part in reactions leading to colour formation whereas 2-furancarboxylic acid does not. The effect of iron ions on the colour formation appears to depend on their oxidation state. The brightness loss caused by either 5-formyl-2-furancarboxylic acid or reductic acid, present in an amount similar to the content of hexenuronic acid in industrial pulps, was of the same order of magnitude as that observed for industrial pulps aged under the same conditions. Based on these findings, the overall mechanism of thermal yellowing is suggested to involve several stages, including the degradation of hexenuronic acid and the formation of reactive precursors, such as 5-formyl-2-furancarboxylic acid or reductic acid, which subsequently take part in the yellowing reactions. The presence of ferrous ions further enhances the discoloration.

  • 76.
    Sevastyanova, Olena
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Gellerstedt, Göran
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    The influence of various oxidizable structures on the brightness stability of the bleached chemical pulps2006In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 21, no 1, p. 49-53Article in journal (Refereed)
    Abstract [en]

    The influence on the brightness stability of various oxidizable structures viz.: lignin, hexenuronic acid and other "non-lignin" structures in kraft Pulps was studied. Samples of pulp of different wood species (spruce, birch, eucalyptus) taken from TCF and ECF bleaching sequences were chemically characterised by kappa number fractionation and subjected to accelerated ageing. It was shown that the selective removal of all oxidizable structures of carbohydrate origin present in the pulp significantly improved the brightness stability. The thermal yellowing of the pulps was found to be proportional to the content of hexenuronic acid groups regardless of the pulp origin or bleaching history. Quantitative determination of the changes during ageing showed that 2-furancarboxylic acid and 5-formyl-2-furancarboxylic acid are formed in the course of decomposition of hexenuronic acid. The difference between the original amount of hexenuronic acid groups in a pulp sample and the sum of the remaining hexenuronic acid together with the 2-furancarboxylic acid and 5-formyl-2-furancarboxylic acid suggests that the latter are involved in further reactions leading to the formation of chromophoric structures. It was also found that 2,3-dihydroxy-2-cyclopenten-1-one (reductic acid) is formed during the ageing.

  • 77. Taube, Fabian
    et al.
    Shchukarev, Andrei
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Gellerstedt, Göran
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Agnemo, Roland
    Peroxomolybdate catalysts in pulp hydrogen peroxide bleaching: Improvement in hexeneuronic acid removal and delignification2008In: TAPPI Journal, ISSN 0734-1415, Vol. 7, no 3, p. 8-14Article in journal (Refereed)
    Abstract [en]

    We have studied the catalytic effects of peroxomolybdates, i.e., [MoO(O-2)(2)(OH)(H2O)], on hydrogen peroxide bleaching on hardwood and softwood pulps in terms of kappa number reduction, hexeneuronic acid (HexA) removal, and delignification. We found that, in the case of hardwood pulp, the decrease of HexA in the peroxomolybdate bleaching stage corresponds to more than 60% of the kappa number reduction obtained in that stage. In the case of pine pulp, inclusion of molybdate in the peroxide stage lowered the kappa number by 4.1. This work also shows that hydrogen peroxide, in the absence of molybdate, did not react to any noticeable extent with neither the lignin model compounds or HexA, under otherwise similar conditions. In order to investigate the oxidation mechanism, lignin model compounds with different side chain structures were reacted with peroxomolybdate. H-1-NMR revealed that lignin model compounds with double bond structure in conjugation with the aromatic ring has an extreme fast speed to react with the peroxomolybdate catalysts, systems, presumably through hydroxylation reactions. This mechanism was supported by XPS analysis of the pulp samples, in which the activated hydrogen peroxide was found to act in a similar fashion on surface lignin as well. In conclusion, molybdate activated hydrogen peroxide can be considered a very efficient and selective bleaching agent.

  • 78.
    Villaverde, José Juan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Ligero, Pablo
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    de Vega, Alberto
    Mild peroxyformic acid fractionation of Miscanthus x giganteus bark. Behaviour and structural characterization of lignin2012In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 35, no 1, p. 261-268Article in journal (Refereed)
    Abstract [en]

    Miscanthus x giganteus bark was subjected to mild fractionation with peroxyformic acid by a two stage process. A factorial experimental design was used to study and quantify the effect of the variables (formic acid concentration (80-90%), hydrogen peroxide concentration (0.2-0.4%), temperature of the first stage (60-80 degrees C), and treatment time of the second stage (60-120 min)) on the main parameters of fractionation: pulp yield, remaining lignin and total polysaccharides in pulp. The dependence of lignin precipitation rate on hydrogen peroxide concentration in liquor was also studied. Hydrogen peroxide concentrations inferior to 0.5% seems to be suitable to recover high percentages of lignin. The isolated lignin was analysed by 2D-HSQC, (13)C- and (31)P NMR spectroscopy, FTIR spectroscopy, size-exclusion chromatography and chemical analysis. The most important chemical modifications taken place in the lignin during the fractionation were identified: beta-O-4' cleavage and hydrolysis of LC-bond structures. The C9-formula was also determined: C(9)H(6.81)O(2.90)(OCH(3))(0.68)(COOH)(0.07)(OH(Ph))(0.38)(OH(Al))(0.33) .

  • 79. Villaverde, Juan Jos
    et al.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Ligero, Pablo
    Vega, Alberto de
    Structural characterization of Acetosolve lignin from Miscanthus sinensis2008In: 10th EWLP: European Workshop on Lignocellulosics and Pulp, 2008, p. 262-265Conference paper (Refereed)
  • 80.
    Villaverde, Juan Jose
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Ligero, Pablo
    de Vega, Alberto
    Native Lignin Structure of Miscanthus x giganteus and Its Changes during Acetic and Formic Acid Fractionation2009In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 57, no 14, p. 6262-6270Article in journal (Refereed)
    Abstract [en]

    Milled wood lignin (MWL) and acetic and formic acid lignin (AL and FL) from Miscanthus x giganteus bark were produced, respectively, before and after organosolv fractionations under optimal conditions, in terms of organic and hydrochloric acid concentrations, liquid/wood ratio, and reaction time. In order to study the M. x giganteus native lignin structure and its modifications during the fractionation process, the lignins were studied by two-dimensional heteronuclear single quantum coherence (2D-(HSQC)), C-13- and P-31 nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR), size-exclusion chromatography (SEC) both before and after thioacidolysis, and elemental analysis. In addition, chemical composition analysis was performed on ash, Klason lignin, and carbohydrate content. The analyses demonstrated that M. x giganteus native lignin (MWL) is highly acylated at the C-gamma of the lignin side chain (46%), possibly with p-coumarate and/or acetate groups. This is newsworthy since several earlier Studies showed that acylation at the gamma-carbon commonly occurs in C-3 and CAM grasses, whereas M. x giganteus is a C-4 grass. Furthermore, M. x giganteus showed a low S/G ratio (0.7) and a predominance of beta-O-4' linkages (up to 93% of all linkages). AL and FL lose part of these linkages during organosolv fractionation (up to 21 and 32%, respectively). The p-coumarate groups resist fractionation processes and are still present in high quantities in AL and FL. During the fractionation process, lignin is acetylated (acetic acid process) and condensed, with the G units condensing more than S units. M. x giganteus MWL contains a high content of carbohydrates (22.8%), suggesting that it is a lignin-carbohydrate complex (LCC). AL and FL showed low carbohydrate contents because of the breaking down of the LCC structures. AL and FL have high molecular weights and low polydispersities, and are high in phenolic content, qualities that make these suitable for different applications. These results suggest that refinement of M. x giganteus via organosolv processes could potentially turn this grass into a valuable source of both fiber and lignin.

  • 81.
    Wang, M.
    et al.
    School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China.
    Zhao, Yadong
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Li, Jiebing
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    From hollow lignin microsphere preparation to simultaneous preparation of urea encapsulation for controlled release using industrial kraft lignin via slow and exhaustive acetone-water evaporation2020In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 4, no 1, p. 77-87Article in journal (Refereed)
    Abstract [en]

    Lignin nano/microparticles have recently attracted growing interest for various value-additive applications of lignin, especially encapsulation. In this study, in order to establish a highly efficient and highly productive preparation process to effectively utilize technical lignin, a brand-new, slow and exhaustive solution evaporation process following a simple, self-assembly principle was developed using industrial softwood kraft lignin (SKL) from a starting acetone-water (80/20, v/v) solution to recover 100% of the lignin as homogeneous and well-shaped microspheres. The prepared microspheres had a typical average diameter of 0.81 ± 0.15 μm and were hollow with very thin shells (of nanoscale thickness). Based on this developed technique, encapsulation of urea by these lignin microspheres was directly achieved using the same process as hollow lignin microspheres with urea attached to the outside and entrapped inside of the wall. Two distinct urea release rates were observed for the urea-encapsulated microspheres: a fast release of the urea outside the shell wall and a slow (controlled) release of the urea inside the shell wall. The encapsulation efficiency was as high as 46% of the trapped urea as encapsulated inside the lignin microspheres. The slow and exhaustive solution evaporation procedure reported here is a simple and straightforward method for the valorization of industrial kraft lignin as hollow microspheres with controllable, homogeneous and desired morphologies, and especially for the direct preparation of lignin-based encapsulating fertilizers for controlled release.

  • 82.
    Wang, Miao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Innventia AB, Sweden.
    Sjöholm, Elisabeth
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Innventia AB, Sweden.
    Fast and reliable quantification of lignin reactivity via reaction with dimethylamine and formaldehyde (Mannich reaction)2017In: Holzforschung, ISSN 0018-3830, Vol. 71, no 1, p. 27-34Article in journal (Refereed)
    Abstract [en]

    The influence of pH on the Mannich reaction (amino alkylation in the presence of formaldehyde) has been analyzed by liquid chromatography-mass spectrometry (LC-MS) with vanillin (VA) as a model compound and a purified softwood kraft lignin (SKL) as a substrate. The reaction products of VA were studied at pH 5, 7, and 9 at 60 degrees C for 4 h. The Mannich adduct and side reaction products with methylene bridge were found at both pH 7 and 9, while only di-substituted by-products were observed at pH 5. Nitrogen contents determined from blank runs were substantial at pH 5 and negligible at pH 7. In VA or SKL, the resulting N-contents at pH 7 corresponded to a 76 or 62 mol% of the theory, respectively, i.e. based on the available C-5 positions in phenolic guaiacyl units (G-units). In the case of SKL, P-31-NMR analysis confirmed a 77% conversion of all phenolic G-units into their C-5 substituted derivatives. The Mannich reaction should be performed on lignin at pH 7 for 1 h to suppress unwanted side reactions, which could be observed by LC-MS under other pH conditions. The reaction is suitable for fast and reliable determination of reactive C-5-positions in lignin by multiplication of the N-content of the reaction products with a factor of 1.6.

  • 83.
    Wang, Miao
    et al.
    KTH, School of Industrial Engineering and Management (ITM).
    Sjöholm, Elisabeth
    INNVENTIA AB, Stockholm, Sweden.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Improved method for lignin reactivity quantification for lignin substitution of phenol in preparation of phenol-formaldehyde polymer2014In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247Article in journal (Other academic)
  • 84.
    Wang, Miao
    et al.
    KTH. RISE Res Inst Sweden, SE-11486 Stockholm, Sweden..
    Zhao, Yadong
    KTH.
    Li, Jiebing
    KTH. RISE Res Inst Sweden, SE-11486 Stockholm, Sweden..
    Demethylation and other modifications of industrial softwood kraft lignin by laccase-mediators2018In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 72, no 5, p. 357-365Article in journal (Refereed)
    Abstract [en]

    Substitution of phenol in phenol-formaldehyde (PF) resin preparations by technical lignins is hindered by the inherently lower reactivity of lignin compared to phenol. Demethylation of an industrial softwood kraft lignin (SKL) to improve its reactivity is the focus of this paper. To this purpose, kraft lignin (KL) was treated with two commercial laccases, NS51002 (L1) and NS51003 (L2), for 24 h in combination with three mediators, 2,2'-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 1-hydroxybenzotriazole (HBT) and 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO). The characterizations of the reaction solution and the resultant KL showed that methanol was released as a result of the methoxy group splitting from the aromatic rings, while such demethylation was dependent on the laccase-mediator system (LMS). The catechol structures formed, which were further oxidized to a quinone structures prone to polymerization, led to molecular mass increment. Also this reaction was LMS dependent. The same is true to the cleavage of beta-O-4' linkages, which resulted in depolymerization. The L1-ABTS, L1-TEMPO and L2-HBT combinations are the most efficient and the resulting modified lignin would be suitable to phenol substitution. Challenging is the lignin polymerization following the demethylation, especially in case of L1-ABTS, which might inhibit the reactivity of the treated lignin.

  • 85.
    Zhang, Yujia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    On renewable film made from spruce glucomannan2012In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 243Article in journal (Other academic)
  • 86.
    Zhang, Yujia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Chalmers, Sweden.
    Lindström, Mikael E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Chalmers, Sweden.
    Mischnick, Petra
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Tech Univ Carolo Wilhelmina Braunschweig, Germany.
    Reactivity investigation of glucomannan from spruce2014In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247, no 113-CELLArticle in journal (Other academic)
  • 87.
    Zhang, Yujia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Mischnick, Petra
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Reactivity investigation of glucomannan from spruce2013Conference paper (Refereed)
  • 88.
    Zhang, Yujia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Mischnick, Petra
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Technische Universität Braunschweig, Germany .
    Relative reactivities in the O-methylation of glucomannans: the influence of stereochemistry at C-2 and the solvent effect2015In: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 402, p. 172-179Article in journal (Refereed)
    Abstract [en]

    The main hemicellulose in softwood, glucomannan (GM), structurally resembles cellulose but has quite different physical and chemical properties. In addition to branching and original acetylation, the only other difference between these two beta-1,4-linked glycans is the configuration at C-2 in approximately 80% of the sugar residues. In contrast to glucose, the 2-OH in mannose has an axial orientation. The influence of this stereochemistry on the relative reactivities of glucosyl compared to mannosyl units in methylation reactions are studied in this work. Glucomannan isolated from spruce (SGM) and commercially available konjac glucomannan (KGM) was methylated in DMSO/Li-dimsyl/MeI and water/NaOH/MeI system, respectively. In the early stage of the reaction, the glucose part of the SGM achieved slightly higher DS values than the mannose residues, but the overall relative rate constants were close to 1:1. The order of reactivities in glucose was k(2) > k(3) > k(6) and k(3) > k(2) > k(6) for mannose (in DMSO/Li-dimsyl/MeI). The rate constants did not remain constant, but k(3) decreased when k(2) increased for both epimeric sugars. In water/NaOH/MeI, the methylation of the primary 6-OH was much more pronounced with an order of reactivity of O-6 > O-2 > O-3 for mannose and O-2 > O-6 > O-3 for glucose. The results are discussed with respect to the OH-acidity and the stereoelectronic, sterical, and solvent effects.

  • 89.
    Zhang, Yujia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Lindström, Mikael E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Stepan, A.
    Gatenholm, P.
    Spruce glucomannan; preparation, purification, characterization and derivatization2011In: Int. Symp. Wood, Fiber Pulping Chem. - Proc., ISWFPC, 2011, p. 478-483Conference paper (Refereed)
    Abstract [en]

    (Galacto)glucomannans are the major hemicelluloses present in softwood species which are important raw materials for Swedish forest industry. In order to utilize spruce wood more comprehensively than by e.g. kraft pulping under a biorefinery concept, it is important to exploit the hemicelluloses as valuable products. In this study, therefore, one water-insoluble glucomannan (GM), composed mainly of glucose and mannose, has been prepared from spruce wood holocellulose in a yield of 6.7% by NaOH/H 3BO 4 extraction and Fehling reagent precipitation. It was further purified and characterized by IC, SEC, 1H- and 13C-NMR and FTIR spectroscopy in terms of carbohydrate composition, molecular size distribution, chemical structure and purity. It has been concluded that the purified GM is composed of galactose, glucose and mannose in a ratio of approximately <0.1:1:3.5. It is large in molecular size (Mp ∼27kDa), almost free from other polysaccharides such as xylan (0.61%) and free from metal ions (<0.2 % ash content). After acetylation, yellowish transparent brittle films were obtained when casted from chloroform solutions of the acetylated GM. Therefore, potential applications of this GM of high values include applications as packaging materials and coatings.

  • 90.
    Zhang, Yujia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Stepan, Agnes
    Gatenholm, Paul
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Chalmers University of Technology, Göteborg.
    Spruce glucomannan: Preparation, structural characteristics and basic film forming ability2013In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 28, no 3, p. 323-330Article in journal (Refereed)
    Abstract [en]

    In this study one representative hemicellulose in spruce wood, low galactosyl substituted glucomannan (GM), has been prepared and purified from holocellulose by NaOH/H3BO4 extraction, Fehling reagent precipitation and HCl regeneration. The GM structure obtained was comprehensively characterized by FTIR, hydrolysis-IC, SEC, and various solution- and solid state NMR spectroscopies. In addition, two pretreatment methods have been evaluated to form films from the GM. It was found that the spruce GM is composed of galactose, glucose and mannose in a ratio of 0.03:1:3.4. The molecular masses are around 255 kDa (Mw) against pullulan standards. The GM was almost free from other polysaccharides such as xylan (0.61%) and free from metal ions (<0.2% ash content). After blending with glycerol or pre-acetylation, two yellowish transparent films have been obtained after solution casting. For the former, water affinity was observed while for the latter water resistance was noticed. Potential high value applications of this GM include packaging and coatings in food and pharmaceutical industry.

  • 91.
    Zhao, Yadong
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Ascidian bioresources: common and variant chemical compositions and exploitation strategy examples of Halocynthia roretzi, Styela plicata, Ascidia sp and Ciona intestinalis2016In: Zeitschrift für Naturforschung C - A Journal of Biosciences, ISSN 0939-5075, E-ISSN 1865-7125, Vol. 71, no 5-6, p. 165-180Article in journal (Refereed)
    Abstract [en]

    To explore abundant marine ascidian bioresources, four species from two orders have been compared in their chemical compositions. After a universal separation of the animal body into two fractions, all tunics have been found rich in carbohydrate contents, while all inner body tissues are richer in proteins. Cellulose is present almost exclusively in the tunics and more in the order Stolidobranchia, while more sulfated polysaccharides are present in Phlebobranchia species. Almost all proteins are collagens with a high essential amino acid index and high delicious amino acid (DAA) content. All fractions also have high contents of good-quality fatty acids and trace minerals but low toxic element contents, with different sterols and glycosaminoglycans. There are species-specific characteristics observed for vanadium accumulation and sterol structures which are also meaningful for ascidian chemotaxonomy and resource exploitation. It is suggested that in addition to the present utilizations of tunics for cellulose production and of some species' inner body tissues as human food, one should explore all species' inner body tissues as human foods and all tunics as food or animal feed with the contained cellulose as dietary fiber. Collagens, sulfated polysaccharides, glycosaminoglycans, sterols and trace elements could be explored as byproducts for, e.g. pharmaceutical and chemical industries.

  • 92.
    Zhao, Yadong
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Comprehensive comparison between woody and tunicate celluloses2014In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247, p. 95-CARB-Article in journal (Other academic)
  • 93.
    Zhao, Yadong
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Comprehensive lipid classification and its structural characterization of Tunicate Ciona intestinalis2013In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245Article in journal (Other academic)
  • 94.
    Zhao, Yadong
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Excellent chemical and material cellulose from tunicates: diversity in cellulose production yield and chemical and morphological structures from different tunicate species2014In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, no 5, p. 3427-3441Article in journal (Refereed)
    Abstract [en]

    The high crystallinity and the high microfibrils aspect ratio of tunicate cellulose (TC) indicate TC's excellent chemical and material applications. However, its quantity and quality from different species have never been systematically reported and compared. In this study, the tunics of Ciona intestinalis (CI), Ascidia sp. (AS), Halocynthia roretzi (HR) and Styela plicata (SP) were processed to TC after an identical prehydrolysis-kraft cooking-bleaching sequence, while the tunicate fibrils were chemically and structurally characterized in situ and during the sequence. All tunics studied were composed of crystalline cellulose embedded with protein, lipids, sulfated glycans and mucopolysaccharides. The native composite structures are all very compact. However, the tunics from Phlebobranchia order (CI and AS) are soft, while those from Stolidobranchia, HR and SP, are hard. Fibrous cellulose could be prepared after removing the lipids, sulfated glycans and mucopolysaccharides through prehydrolysis, protein removal through kraft cooking and a final purification by bleaching. The final product is similar to 100 % pure cellulose which is in large molecular masses, composed of highly crystalline I-beta crystals, in elementary microfibrils form, with high specific surface area and thermal stability. There were lower TC yields from the soft tunics than from the hard ones. The cellulose fibrils had a section shape of lozenges with higher crystallinity. This study demonstrates that TC could be obtained in different yields and exhibited different chemical and morphological structures depending on the species. There is a great potential of tunicate resources for preparing excellent chemical and material cellulose.

  • 95.
    Zhao, Yadong
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Li, Jiebing
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. Bioeconomy, RISE Research Institutes of Sweden, Drottning Kristinas Väg 61, Stockholm, SE-114 86, Sweden.
    Unique and outstanding quantum dots (QD)/tunicate cellulose nanofibrils (TCNF) nanohybrid platform material for use as 1D ink and 2D film2020In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 242, article id 116396Article in journal (Refereed)
    Abstract [en]

    Quantum dots (QD)/polymer materials have wide applications in biological imaging, clinical diagnostics, anti-counterfeiting materials, light-emitting devices and solar cells. The development of QD/cellulose nanofibrils (CNF) hybrids with a more perfect structure and excellent properties is important for improving known applications. A unique tunicate CNF (TCNF) was homogeneously blended with outstanding CdSe/CdS core/shell QD to prepare a novel QD/TCNF hybrid. The QD were monodispersed on a single TCNF fibril surface as an evenly distributed monolayer with an extremely high packing density and no visible aggregation. The prepared hybrid is an excellent platform nanomaterial which was demonstrated by its good writing fidelity when applied as a 1D ink and by its good processability in the preparation of 2D films with acceptable transparency and flexibility. This one-step direct blending approach provides a facile shortcut to effectively fabricate cellulose-based high-performance functional QD nanomaterials at the single-fibril level.

  • 96.
    Zhao, Yadong
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Li, Liebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Ascidian bioresources: common and variant chemical compositions and exploitation strategy- Examples of Halocynthia roretzi, Styela plicata, Ascidia sp. and Ciona intestinalisManuscript (preprint) (Other academic)
    Abstract [en]

    Four ascidian species have been compared on chemical compositions. All animal tunics have rich carbohydrate contents, while all inner body tissues are richer in proteins. Cellulose is present almost exclusively in the tunics and more in the order Stolidobranchia, while more sulfated polysaccharides are present in Phlebobranchia species. Almost all proteins are collagens with a high essential amino acid index and high delicious amino acid content. All fractions also have high contents of good-quality fatty acids and trace minerals but low toxic element contents, with different sterols and glycosaminoglycans. Therefore, in addition to the present utilizations of tunics for cellulose production and of some species’ inner body tissues as human food, one should explore all species’ inner body tissues as human foods and all tunics as food or animal feed with the contained cellulose as dietary fiber. Collagens, sulfated polysaccharides, glycosaminoglycans, sterols and trace elements could be explored as byproducts.

  • 97.
    Zhao, Yadong
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Moser, Carl
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Lindström, Mikael E
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Henriksson, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Cellulose Nanofibers from Softwood, Hardwood, and Tunicate: Preparation-Structure-Film Performance Interrelation2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 15, p. 13508-13519Article in journal (Refereed)
    Abstract [en]

    This work reveals the structural variations of cellulose nanofibers (CNF) prepared from different cellulose sources, including softwood (Picea abies), hardwood (Eucalyptus grandis × E. urophylla), and tunicate (Ciona intestinalis), using different preparation processes and their correlations to the formation and performance of the films prepared from the CNF. Here, the CNF are prepared from wood chemical pulps and tunicate isolated cellulose by an identical homogenization treatment subsequent to either an enzymatic hydrolysis or a 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-mediated oxidation. They show a large structural diversity in terms of chemical, morphological, and crystalline structure. Among others, the tunicate CNF consist of purer cellulose and have a degree of polymerization higher than that of wood CNF. Introduction of surface charges via the TEMPO-mediated oxidation is found to have significant impacts on the structure, morphology, optical, mechanical, thermal, and hydrophobic properties of the prepared films. For example, the film density is closely related to the charge density of the used CNF, and the tensile stress of the films is correlated to the crystallinity index of the CNF. In turn, the CNF structure is determined by the cellulose sources and the preparation processes. This study provides useful information and knowledge for understanding the importance of the raw material for the quality of CNF for various types of applications.

  • 98.
    Zhao, Yadong
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Moser, Carl
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Wood Chemistry and Pulp Technology. Valmet AB, Sundsvall, Sweden..
    Lindström, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Henriksson, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Film formation and performance of different nanocelluloses obtained from different cellulose sources after different preparation processes2017In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 253Article in journal (Other academic)
  • 99.
    Zhao, Yadong
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Qin, Haiyan
    Niu, Yuan
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Peng, Xiaogang
    Direct incorporation of high-quality zinc-blende CdSe/CdS core/shell nanocrystals onto tunicate cellulose nanocrystals as high performance luminescent functional nanostructural materialManuscript (preprint) (Other academic)
  • 100.
    Zhao, Yadong
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Ray, Jessica Louise
    Skaar, Katrine Sandnes
    Thompson, Eric M.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Troedsson, Christofer
    Molecular analysis of the tunicate Ciona intestinalis intestine: contribution of prokaryotes and eukaryotic parasitesManuscript (preprint) (Other academic)
123 51 - 100 of 107
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