Characterization of Lignins from Organosolv Pulping According to the Organocell Process, Part 2. Residual Lignins

Lindner, Albert; Wegener, G.

doi:10.1080/02773818908050310

Cited by 17 publications

(4 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A C 9 molecular weight of approximately 190 was previously reported for softwood organosolv lignins (Lindner and Wegener 1989). The results for lignins in pulps produced by ethanol/water solvolysis catalyzed by 0.005M or 0.01M H 2 SO 4 are now being reported.…”

Section: Introductionmentioning

confidence: 61%

Lignin Analysis by Permanganate Oxidation. II. Lignins in Acidic Organosolv Pulps

Bose¹,

Wilson²,

Hausch³

et al. 1999

Holzforschung

View full text Add to dashboard Cite

The permanganate oxidation method was used to analyze residual lignins in Norway spruce (Picea abies) organosolv pulps. The pulps were produced by ethanol water solvolysis catalyzed by 0.005M or 0.01M H 2 SO 4 at 175°C. Condensation reactions of residual lignin occurred at a significant rate when the ethanol volume fraction was 0 % but not when it was ≥ 51 %. There was selective removal of uncondensed guaiacyl units when mixtures of 51 %, 76%, and 91% ethanol were used. The condensed units in the native lignin were less reactive and accumulated in the fibers. They constituted > 60 % of the C 9 units by the time 80 % delignification was achieved. A limited amount of results are presented for a kraft pulp with hopes of enhancing the credibility of permanganate oxidation as an analytical tool for residual lignins.

show abstract

Section: Introductionmentioning

confidence: 61%

Lignin Analysis by Permanganate Oxidation. II. Lignins in Acidic Organosolv Pulps

Bose¹,

Wilson²,

Hausch³

et al. 1999

Holzforschung

View full text Add to dashboard Cite

show abstract

“…In order to obtain all the precipitable Organocell lignin the pH was further lowered to 2.0 by adding diluted HCl.The subsequent Steps for isolating and analyzing the precipitated lignins have been described elsewhere (Lindner andWegener 1988;1990a;b).The lignins were termed according to the current density applied: Sp E/200 = spruce lignin treated with 200 mA/cm 2 Sp E/100 = spruce lignin treated with 100 mA/cm 2 402 J.G. L bbecke, A. Lindner, G. Wegener and D.W. Wabner ______^_»^·^H olzforschung Figure l shows that three quarter of the total submitted electric Charge is consumed when the anolyte is still alkaline.…”

Section: Lignin Precipitation and Analysismentioning

confidence: 99%

Anodic Modification of Lignins during Electrolysis in the Organocell Process

Löbbecke¹,

Lindner²,

Wegener³

et al. 1990

Holzforschung

View full text Add to dashboard Cite

Pulping liquor from the 5 t/day demonstration plant of Organocell GmbH, Munich, was electrolyzed with different current densities. The analysis of the isolated lignins revealed considerable changes of lignin structure during electrolysis. These changes included polymerization reactions involving the formation of C-and O-condensed interunit linkages and reactions of the side-chain such äs decomposition of enol ethers and increase of COOH, CO and OH a |j. groups. The extent of the observed reactions was found to be highly dependent on the current density. With the exception of OH a ü. groups and residual sugars, the degree of structural modification was inversely proportional to current density.

show abstract

“…The efficiency of the fractionation was investigated using a fractional factorial design on reaction temperature, catalyst loading, and methanol-to-water ratio. The conditions were derived from literature reporting on the Organocell process [12,[15][16][17][18]. The results were compared to two lab-scale Kraft processes and three previously reported acid-catalyzed organosolv fractionations [21].…”

Section: Introductionmentioning

confidence: 99%

Influence of Base-Catalyzed Organosolv Fractionation of Larch Wood Sawdust on Fraction Yields and Lignin Properties

et al. 2019

View full text Add to dashboard Cite

Lignocellulose-based biorefineries are considered to play a crucial role in reducing fossil-fuel dependency. As of now, the fractionation is still the most difficult step of the whole process. The objective of this study is to investigate the potential of a base-catalyzed organosolv process as a fractionation technique for European larch sawdust. A solvent system comprising methanol, water, sodium hydroxide as catalyst, and anthraquinone as co-catalyst is tested. The influence of three independent process variables, temperature (443–446 K), catalyst loading (20–30% w/w), and alcohol-to-water ratio (30–70% v/v), is studied. The process conditions were determined using a fractional factorial experiment. One star point (443 K, 30% v/v MeOH, 30% w/w NaOH) resulted in the most promising results, with a cellulose recovery of 89%, delignification efficiency of 91%, pure lignin yield of 82%, residual carbohydrate content of 2.98% w/w, and an ash content of 1.24% w/w. The isolated lignin fractions show promising glass transition temperatures (≥424 K) with high thermal stabilities and preferential O/C and H/C ratios. This, together with high contents of phenolic hydroxyl (≥1.83 mmol/g) and carboxyl groups (≥0.52 mmol/g), indicates a high valorization potential. Additionally, Bjorkman lignin was isolated, and two reference Kraft cooks and a comparison to three acid-catalyzed organosolv fractionations were conducted.

show abstract

Characterization of Lignins from Organosolv Pulping According to the Organocell Process, Part 2. Residual Lignins

Cited by 17 publications

References 12 publications

Lignin Analysis by Permanganate Oxidation. II. Lignins in Acidic Organosolv Pulps

Lignin Analysis by Permanganate Oxidation. II. Lignins in Acidic Organosolv Pulps

Anodic Modification of Lignins during Electrolysis in the Organocell Process

Influence of Base-Catalyzed Organosolv Fractionation of Larch Wood Sawdust on Fraction Yields and Lignin Properties

Contact Info

Product

Resources

About