Kohlenstoff-13-NMR-Spektren von Ligninen, 6. Lignin- und DHP-Acetate

Nimz, Horst; Lüdemann, H.‐D.

doi:10.1515/hfsg.1976.30.2.33

Cited by 88 publications

(48 citation statements)

References 10 publications

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“…The relative intensity at 168.5 ppm was much smaller in Nalita dioxane lignin than aspen dioxane lignin, which suggested a lower free phenolic hydroxyl group in Nalita lignins. Red beech had smaller relative intensity than softwood lignin at 168.5 ppm as found by Nimz et al (1976). The signal at 121.3-122.0 ppm indicates the presence of phydroxyphenyl group in Nalita and aspen dioxane lignin.…”

Section: Nmrmentioning

confidence: 70%

Isolation and Characterization of Lignin from Tropical and Temperate Hardwood

Jahan

Mun

2010

Bangladesh J. Sci. Ind. Res.

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Dioxane and milled wood lignins (MWL) were isolated from tropical hardwood, Nalita (Trema orientalis) and temperate hardwood, aspen. These lignins were characterized by UV, FTIR, 1 H-NMR and 13 C-NMR spectroscopy, alkaline nitrobenzene oxidation, molecular weight determination, elemental and methoxyl analysis. The structural analysis revealed that Nalita and aspen lignin is syringyl-guaiacyl type. Aspen lignin had higher syringyl unit than Nalita lignin. The β -O-4 type linkages are the main interunit linkages and more abundant in aspen than Nalita. Dioxane lignin showed higher free phenolic hydroxyl group than MWL in both species. The weight average molecular weight of aspen lignin was lower than that of Nalita lignin. Nalita and aspen lignins contained both erythro and threo configuration, but erythro proton gave stronger peak. A UV absorption maximum of aspen lignin was at 274 nm, whereas it was shifted to 280 nm for Nalita lignin.

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Section: Nmrmentioning

confidence: 70%

Isolation and Characterization of Lignin from Tropical and Temperate Hardwood

Jahan

Mun

2010

Bangladesh J. Sci. Ind. Res.

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“…Only rarely do two monomers couple to form a dimer. Lignification thereby produces structures that are in different proportions from those encountered in synthetic lignins obtained from high levels of monomer-coupling products (bulk polymerization) (26)(27)(28). Synthetic lignins are usually rich in cinnamyl alcohol endgroups X.…”

Section: Resultsmentioning

confidence: 99%

NMR characterization of altered lignins extracted from tobacco plants down-regulated for lignification enzymes cinnamylalcohol dehydrogenase and cinnamoyl-CoA reductase

Ralph

Hatfield²,

Piquemal³

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

181

165

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Homologous antisense constructs were used to down-regulate tobacco cinnamyl-alcohol dehydrogenase (CAD; EC 1.1. Lignins are phenolic polymers essential for mechanical support, defense, and water transport in vascular terrestrial plants (1-3), but they are a major obstacle to efficient utilization of plants for paper making or animal feed. A recent approach toward improved utilization has been the down-regulation of enzymes involved in the lignin monomer biosynthetic pathway (Fig.

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“…This deshielding indicates the presence of hydroxyl groups (Lindström and österberg 1984). Signals Nos 37 and 38 are shifted downfield in spectra of acetylated samples indicating hydroxyl groups adjacent to these carbons (Nimz and Lüdemann 1976). Signals Nos 32, 35 and 36 are not shifted in acetylated samples, which may indicate that these signals arise from carbons bonded to ether structures.…”

Section: Aliphatic Carbonsmentioning

confidence: 95%