Chemical processing of lignocellulosics

Nimz, Horst; Casten, R. F.

doi:10.1007/bf02611993

Cited by 95 publications

(40 citation statements)

References 5 publications

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“…29 In this case, a considerable extraction of lignin could be also achieved with aqueous organic solvents under acidic or alkaline conditions. The solvent primarily acts on the promotion of vegetal tissue impregnation and the solubilization of the lignin fragments so produced.…”

Section: Lignin Yield and Puritymentioning

confidence: 99%

Comparative study of three lignin fractions isolated from mild ball‐milled Tamarix austromogoliac and Caragana sepium

Sun

Zhai³

et al. 2008

J of Applied Polymer Sci

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Six lignin fractions from mild ball-milled Tamarix austromogoliac (TA) and Caragana sepium (CS) were sequentially isolated with 80% dioxane containing 0.05M HCl at 758C for 4 h, 50% aqueous ethanol containing 1M triethylamine at 708C for 4 h, and 8% aqueous NaOH at 458C for 3 h. The results showed that the successive treatments made it possible to isolate lignin from wood with a high yield and purity, in which 89.4 and 90.6% of the original lignin from TA and CS were released, respectively. The lignin fractions isolated with the three-step method were analyzed with Fourier transform infrared, 1 H-and 13 C-NMR, alkaline nitrobenzene oxidation, and gel permeation chromatography. It was found that the three lignin fractions isolated from TA were rich in syringyl units, and the molar ratio of the relatively total moles of vanillin, vanillic acid, and acetovanillin to the relatively total moles of syringaldehyde, syringic acid, and acetosyringone decreased from 1 : 2.6 to 1 : 3.2 to 1 : 3.6 in the lignin preparations, whereas this ratio in the corresponding lignin fractions isolated from CS was found to be 1.4 : 1, 1.1 : 1, and 1 : 1.4, respectively. More importantly, the results revealed that the sequential extractions of the mild ball-milled TA and CS with 80% acidic dioxane, 50% alkaline ethanol, and 8% aqueous NaOH under the conditions used did not significantly cleave the b-O-4 and a-O-4 linkages in lignin macromolecules.

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Section: Lignin Yield and Puritymentioning

confidence: 99%

Comparative study of three lignin fractions isolated from mild ball‐milled Tamarix austromogoliac and Caragana sepium

Sun

Zhai³

et al. 2008

J of Applied Polymer Sci

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“…Acetic acid delignification (Acetosolv) has been firstly designed in 1986 as a pulping method for pinewood [30]. An aqueous mixture enriched in acetic acid with small amounts of hydrochloric acid is maintained under reflux at atmospheric pressure for a given time.…”

Section: Organosolv With Acetic Acidmentioning

confidence: 99%

“…An aqueous mixture enriched in acetic acid with small amounts of hydrochloric acid is maintained under reflux at atmospheric pressure for a given time. A set of experimental conditions can be identified in order to obtain pulps with kappa numbers below 30 [30]. The process can be also operated without mineral acid (Acetocell) at comparatively high temperatures [31].…”

Section: Organosolv With Acetic Acidmentioning

confidence: 99%

Miscanthus x giganteus as a Source Of Biobased Products Through Organosolv Fractionation: A Mini Review

Villaverde¹,

Ligero²,

Vega

2010

TOASJ

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This paper deals with the chemical treatments with selected organic compounds that have been applied to Miscanthus to upgrade it, for pulp production or fractionation purposes. Organosolv processes have demonstrated their effectiveness as fractionation treatments; therefore special emphasis is placed on these systems and, in particular, those making use of carboxylic acids. That is, Acetosolv process that uses acetic acid-water-hydrochloric acid mixtures as delignifying agents, the process with formic acid-water-hydrochloric acid and the Milox process, which replaces the hydrochloric acid in the medium by hydrogen peroxide, thus forming peroxyacetic acid. Furthermore, we present the results of the characterizations that have been made in relation to extractives and lignin of Miscanthus. It also is analyzed the major changes undergone by lignin during organosolv treatments. Finally, some progresses in the field of TCF bleaching of the cellulose pulps obtained are summarized.

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“…Organosolv pulping processes are designed to solve the high capital cost and environmental problems and to effectively use the total lignocellulosic material. 1 Acetosolv pulping, an example of organosolv pulping processes, is based on the treatment of the lignocellulosic material with an acetic acid solution containing a catalytic amount of HCl at 1108C and atmospheric pressure for 3-6 h. 2 With this process, the lignocellulosic material can be fractionated into pulp, monosaccharide, and lignin. The pulp can be used for paper and cellulose derivatives and can also be converted to glucose.…”

Section: Introductionmentioning

confidence: 99%

Some physical properties of acetosolv lignins from bagasse

Shukry

Fadel

Agblevor

et al. 2008

J of Applied Polymer Sci

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Acetosolv-solubilized lignins were characterized by their solubility in different organic solvents, Fourier transform infrared, 13 C-NMR, UV, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis. Solvents having a solubility parameter in the range of 10-12.7 and a hydrogenbonding parameter in the range of 3.6-5 were considered good solvents for acetosolv lignins. Fourier transform infrared spectra of the lignins were typical for lignins containing p-hydroxy phenylpropane (H), guaiacyl (G), and syringyl (S) units. The lignins contained more conjugated and fewer nonconjugated C¼ ¼O groups, and the guaiacyl groups were etherified and condensed.13 C-NMR confirmed partial acetylation of the lignins and the presence of b-O-4 and b-5 linkages. Acetosolv lignins also showed the typical UV spectrum of annual plants.The effects of the acetic acid concentration and pulping time on the molecular weights of the lignins were explained with the presieving and condensation concepts. The thermal behavior of the acetosolv lignins was also studied.

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Chemical processing of lignocellulosics

Cited by 95 publications

References 5 publications

Comparative study of three lignin fractions isolated from mild ball‐milled Tamarix austromogoliac and Caragana sepium

Comparative study of three lignin fractions isolated from mild ball‐milled Tamarix austromogoliac and Caragana sepium

Miscanthus x giganteus as a Source Of Biobased Products Through Organosolv Fractionation: A Mini Review

Some physical properties of acetosolv lignins from bagasse

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