Über neuere Versuche zur Trennung von Cellulose und Inkrusten verschiedener Hölzer

Kleinert, Th.; Tayenthal, K. v.

doi:10.1002/ange.19310443903

Cited by 76 publications

(30 citation statements)

References 8 publications

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“…[197,204] This problem has long motivated the search for more environmentally-benign alternatives.I nt his context, pulping with organic solvents was first reported in 1931 as an alternative to processes based on sulfurous chemicals. [211] At temperatures of ca. 180 8 8C, the treatment of wood chips in aqueous ethanol (1:1 vol/vol) was demonstrated to be effective at releasing amajor fraction of lignin and hemicelluloses into the solution, enabling the isolation of high-purity cellulosic fibres.…”

Section: Pulping With Organic Solvents-organosolv Ligninsmentioning

confidence: 99%

“…180 8 8C, the treatment of wood chips in aqueous ethanol (1:1 vol/vol) was demonstrated to be effective at releasing amajor fraction of lignin and hemicelluloses into the solution, enabling the isolation of high-purity cellulosic fibres. [211] Despite this valuable finding, pulping in organic solvents remained ad ormant field until the late 1960s,a fter which research activity intensified. [212] At that time,t he umbrella term "Organosolv" was established, in reference to the many variants of delignification processes performed in organic solvents.…”

Section: Pulping With Organic Solvents-organosolv Ligninsmentioning

confidence: 99%

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Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis

et al. 2016

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Lignin is an abundant biopolymer with a high carbon content and high aromaticity. Despite its potential as a raw material for the fuel and chemical industries, lignin remains the most poorly utilised of the lignocellulosic biopolymers. Effective valorisation of lignin requires careful fine‐tuning of multiple “upstream” (i.e., lignin bioengineering, lignin isolation and “early‐stage catalytic conversion of lignin”) and “downstream” (i.e., lignin depolymerisation and upgrading) process stages, demanding input and understanding from a broad array of scientific disciplines. This review provides a “beginning‐to‐end” analysis of the recent advances reported in lignin valorisation. Particular emphasis is placed on the improved understanding of lignin's biosynthesis and structure, differences in structure and chemical bonding between native and technical lignins, emerging catalytic valorisation strategies, and the relationships between lignin structure and catalyst performance.

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Section: Pulping With Organic Solvents-organosolv Ligninsmentioning

confidence: 99%

Section: Pulping With Organic Solvents-organosolv Ligninsmentioning

confidence: 99%

Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis

et al. 2016

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“…6) Liquor/dry straw = 4, sulphidity 25%, active alkali 16%, pulping temperature 160 • of the THFA and kraft pulps. The kraft fibers generally had greater lengths and widths than those of the THFA fibers.…”

Section: )mentioning

confidence: 99%

Tetrahydrofurfuryl Alcohol (THFA) Pulping of Rice Straw

Wang

2009

Journal of Wood Chemistry and Technology

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A 80-95% solution of tetrahydrofurfuryl alcohol (THFA) added with 0.15-0.5% catalytic hydrochloric acid (HCl) was used to pulp rice straw. The pulping conditions applied for organosolv digestions of the straw at atmospheric pressure and 120 • C cooking for 4 h. The characteristics of the digestion, chemical properties of the resulting pulp, and the handsheet physical properties were evaluated. As for the pulp yields, the method has high delignification specificity, at kappa number 20, the yield was ca. 60%, about 15-20% higher than the traditional alkaline pulping method. Furthermore, with increasing THFA concentrations, efficacies of delignification also increased. Increasing the catalyst dosage also caused an increase in delignification. Delignification rate of 120 • C cooking are not so appreciable, but high yield were retained. If cooking temperatures were increased to 130 and 150 • C, although even higher delignification rates were achievable, the yield decreased as well. During the cooking the dissolution of carbohydrate was low, at most 23%, consisting of mostly hemicelluloses, which was as high as 78% of the dissolved carbohydrates. The optimal conditions of the THFA/HCl cooking applied 95% THFA, 0.50% HCl, temperature of 120 • C, and cooking time of 240 min. Residue lignin in the resulting pulp was low, and can be bleached to high brightness easily with a conventional bleaching sequence. If, however, energy and operation efficiency was a primary consideration, then a procedural heating scheme could be employed. The physical properties of the THFA pulp handsheets were inferior to those of the kraft pulp. The main reason was the damage to cellulose sustained during the acidic cooking condition.

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“…Dieses Problem hat schon lange die Suche nach umweltfreundlicheren Alternativen angeregt. In diesem Zusammenhang wurde 1931 erstmals ein Aufschluss mit organischen Lösungsmitteln als Alternative zu Verfahren unter Anwendung schwefelhaltiger Chemikalien beschrieben . Bei Temperaturen von ca.…”

Section: Vorgeschaltete Behandlungunclassified

“…Bei Temperaturen von ca. 180 °C erwies sich die Behandlung von Holzspänen in wässrigem Ethanol (1:1 v/v) als effektiv für die Freisetzung eines Großteils des Lignins und der Hemicellulose in die Lösung, was die Abtrennung von hochreinen Cellulosefasern ermöglichte . Trotz dieses wertvollen Ergebnisses blieb der Aufschluss in organischen Lösungsmitteln bis Ende der 1960er Jahre ein unbearbeitetes Gebiet, danach wurden die Forschungsaktivitäten intensiviert .…”

Section: Vorgeschaltete Behandlungunclassified

Wege zur Verwertung von Lignin: Fortschritte in der Biotechnik, der Bioraffination und der Katalyse

Rinaldi¹,

et al. 2016

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Lignin ist ein reichlich vorhandenes Biopolymer mit hohem Kohlenstoffgehalt und hoher Aromatizität. Trotz seines Potenzials als Rohstoff für die Kraftstoffherstellung und die chemische Industrie ist Lignin noch immer das am wenigsten genutzte Biopolymer der Lignocellulose. Zur effektiven Aufwertung von Lignin ist eine sorgfältige Feinabstimmung mehrerer vorgeschalteter Prozessstufen (d. h. Biotechnik von Lignin, Abtrennung von Lignin und katalytische Umwandlung von Lignin in der Anfangsphase) und mehrerer nachgeschalteter Prozessstufen (d. h. Depolymerisation und Verwertung von Lignin) erforderlich, die den Einsatz und das Zusammenwirken eines breiten Spektrums wissenschaftlicher Disziplinen erfordert. Dieser Aufsatz liefert eine Analyse der neuesten Fortschritte bei der Verwertung von Lignin “vom Anfang bis zum Ende”. Besonderes Augenmerk liegt auf dem verbesserten Verständnis der Biosynthese und Struktur von Lignin, den Unterschieden in Struktur und chemischer Bindung zwischen nativen und technischen Ligninen, den neu aufkommenden Verfahren der katalytischen Verwertung und den Zusammenhängen zwischen Ligninstruktur und Katalysatorleistung.

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Über neuere Versuche zur Trennung von Cellulose und Inkrusten verschiedener Hölzer

Abstract: in der Tat der emartete sein. Eine m e h e wird, wie vorstlehende Kurve zeigt, nicht gebildet, und diese wiirde iibrigens widrigenballs in beiden Fallen gebildet werden.

Cited by 76 publications

References 8 publications

Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis

Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis

Tetrahydrofurfuryl Alcohol (THFA) Pulping of Rice Straw

Wege zur Verwertung von Lignin: Fortschritte in der Biotechnik, der Bioraffination und der Katalyse

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