Milled-wood lignin MWL

Milled wood lignin (MWL) is produced by grinding wood in a rotary or vibratory ball mill. Lignin can be extracted from the resulting powder using solvents such as methylbenzene or... 

Konishi et al. (4,5) reported that milled wood lignin (MWL) treated with the laccase from C. versicolor suffered oxidative polymerization, depolymerization producing... 

Table II. Some Basic Data of Lignins. Milled Wood Lignin = MWL...

Finally, the TFA method can also be applied to materials with a very low polysaccharide content. One example is milled wood lignin (MWL) containing about 1.5% polysaccharides (Figure 8). Another example is fossil wood—a protopinacea, about 180 million years old, which contained about 0.02% polysaccharides, detected by the aid of TFA hydrolysis (Figure 8). 

Figure 8. Chromatograms of the hydrolysates of materials with low polysaccharide content milled wood lignin (MWL) from sprucewood and a 180-million-year-old protopinacea...

Lin and Kringstad (7) confirmed Leary s results in an experiment with a solution of milled wood lignin (MWL) in methylcellusolve water. Irradiation of this solution in a vacuum produced no colour. This solution, opened to air and irradiated, produced the same amount of colour as a solution of milled wood lignin initially irradiated in air. The effect of oxygen on light-induced yellowing of newsprint is further illustrated by the accompanying effect on methoxyl content. Leary found that the methoxyl content of newsprint after irradiation in a vacuum decreased by only 0.1% whereas the same irradiation in air decreased the methoxyl content by 0.4% (6). 

Besides cellulolytic enzyme lignin, the so-called Bjorkman lignin, alternatively referred to as "milled wood lignin" (MWL) is the best preparation known so far, and it has been widely used for structural studies. When wood meal is ground in a ball mill either dry or in the presence of nonswelling solvents, e.g., toluene, the cell structure of the wood is destroyed and a portion of lignin (usually not more than 50%) can be obtained from the suspension by extraction with a dioxane-water mixture. MWL preparations always contain some carbohydrate material. 

Table 5.1.5. Estimation of various conjugated carbonyl groups in spruce milled wood lignin (MWL) (Adler and Marton 1959) and kraft lignin (KL) (Marton 1964) by NaBH4 reduction difference spectroscopy...

Table 5.4.5. Number of carbon atoms in chemical shift ranges in the C NMR spectrum of spruce milled wood lignin (MWL) (Fig 5 4 8a)...

In Table 6 4 3 are shown the yields of monomeric products recovered from milled wood lignin (MWL) and enzymatically liberated lignin (EL) fractions successively isolated from poplar wood and subjected to various degradation procedures (Lapierre 1986) These values reveal that acidolysis, which should allow the characterization of the same lignin structures as thioacidolysis,... 

Both aminolysis and periodate methods have been shown to be comparable in terms of the phenolic hydroxyl content obtained for milled wood lignin (MWL) and kraft lignin from Norway spruce (Mansson 1983) and for Norway spruce and aspen wood meals (Lai et al. 1990). 

Lignin. Milled-wood lignin (MWL) from loblolly pine was obtained by 95% dioxane/water extraction of extractive-free vibratory ball-milled wood. The yield was about 20% based on the lignin in the wood. 

Spruce milled wood lignin (MWL) 21.9 Harden etal. 1980... 

Milled wood lignins (MWLs) Spruce Picea glauca) CyHy 5 02(H20)o 4s(OCH3) 94 1.46 0.28 1.18... 

As biomass samples, sugi Cryptomeria japonica D. Don) and buna (Fagus crenala Blume) woods were selected for supercritical water treatment. In addition, microciystalline cellulose (avicel), glucomannan extracted from softwood dissolving pulp, larch xylan (Shigma Co., Ltd.), and milled wood lignin (MWL) from buna wood were studied to understand reaction behaviors of wood components dunng supercritical water treatment. 

A procedure designed to increase the yield of soluble lignin is the Milled-wood. In this procedure, the wood is ground in a mill for a long period of time and then extracted at room temperature with a solvent and reprecipitated as a Milled-wood lignin (MWL or MW lignin). 

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