Lignin compounds

Lobe, I, Du Preez, C. C., and Amelunga, W. (2002). Influence of prolonged arable cropping on lignin compounds in sandy soils of the South African Highveld. Eur. I. Soil Sci. 53, 553-562. 

The difficulty encountered in separating lignin from the cellulose of wood without the intermediate use of hydrolytic conditions,43 as well as the fact that some workers have isolated uniform, lignin-cellulose complexes,44 has suggested the presence of a carbohydrate-lignin compound. 

Figure 9.44 Lignin compounds, composed of connecting units of monolignols cross linked by carbon to carbon and the dominant /3-0-4 aryl to aryl ether bonds.

Jurkiewicz S (1977) Problem of the effect of interfering factors in the quantitative determination of lignin compounds in aqueous solutions Przegl Papier 33(1) 30-35, Abstr Bull Inst Pap Chem 48 1245... 

Fig. 5.5.7. Typical lignin compound containing an aryl-/f-ether unit...

As shown by thioacidolysis of coniferyl alcohol, compounds 22 and 23 are formed from coniferyl alcohol end groups. They are recovered in larger amounts, relative to compound pair 11, from kraft lignin than from than from milled wood lignin. Compound 24 originates from Q.C-, alkyl aryl ether structures with a-carbonyl substituents via elimination of the Cy hydroxymethyl group (Lapierre 1986, Lapierre et al. 1987). 

Originally, the metals Cu, Cr and As are preferentially bound to the cellulose and lignin compounds in the CCA treated wood, which means that no metals are bound to the hemicellulose compound [9]. 

Burlakov, V. M., E. I. Chupka, D. Chuvashev, andG.V. Ratovskii. 1992. Characterization of electronic structure of ground and excited states of model lignin compounds. III. Quinones and quinone methides. Cell. Chem. Techol. 26(4) 421 26. 

Jakobsons, J., J. Gravitis, V. M. Andrianov, J. Dzehne, and V. G. Dashevsku. 1982. Calculation of frequencies of vibrational spectra of model lignin compounds by the method of atom-atom potential functions. I. Calculation of frequencies of the vibrational spectrum of an aromatic ring. Khim. Drev. 1982(5) 52-57. 

Fig. 3.20 Oxidation of a p-O-4 model lignin compound by ligninase/H202 (after Kirk Farrell 1987). A and B on arrows show which ring is oxidized [ ] = postulated intermediates. 

Fig. 3. 21 Ligninase/H202 mediated oxidation of a (3—1 model lignin compound (after Kirk Farrell 1987).

Although UF cannot recover the low MW sugars in waste from the pulp and paper industry, it can remove lignin compounds and most of the color bodies. 

Do not predry lignin-compounds, normal storage conditions (dry, not more than 25 °C). 

Do not keep lignin-compounds together with other hot polymers cool down immediately, for example, using water. 

The lack of quantitation limits the use of DART in many fields. A new system was proposed, which possesses an option for quantitative analyses [3]. This group demonstrated the analysis of a total extract of Schisandra chinensis fruit on a TLC plate. Three major lignin compounds were identified and quantitated. UV densitometry, TLC-DART-MS, and HPLC-UV were compared as detection methods. For DART analysis, the width of a TLC plate was cut to a narrow slice of 3 mm. The developed... 

Obtained by alkaline CuO oxidation of lignin (compound Vm2Sn) named 2-vanillylacetosyringone [3689]. 

OH Obtained by alkaline CuO oxidation of — / — / lignin (compound VoSVn) named 5-vanil-... 

A rubber/Iignin compound, which is usually given by coprecipitated from a rubber latex, shows a large strength and a high heat resistance in its vulcanizate. However, the rubber/lignin compound has a big problem for a practical use, that is, an extremely high viscosity or a low processability in the unvulcanized state. 

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