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Monomeric lignin, acidolysis products

Lapierre C, Rolando C, Monties B (1983a) Characterization of poplar lignins acidolysis products capillary gas-liquid chromatography of monomeric compounds Holzforschung 37 189-198... [Pg.299]

Lapierre C, Lallemand JY, Monties B (1982) Evidence of poplar lignin heterogeneity by combination of C NMR and H NMR spectroscopy. Holzforschung 36 275-282 Lapierre C, Rolando C, Monties B (1983) Characterization of poplar lignins acidolysis products Capillary gas-liquid and liquid-liquid chromatography of monomeric compounds. Holzforschung 37 189-198... [Pg.351]

The crude Bjorkman lignin acidolysis mixture contained both polymeric material and a number of more or less low molecular, chromato-graphically visible products in addition to ketol (XII) and was considered to be a potential source not only of further monomeric but also of dimeric and oligomeric degradation products. The polymeric material was readily removed by filtering the crude mixture of reaction products through a short silica gel column (solvent, dioxane-benzene 1 3). [Pg.39]

Lignins can be detected and characterized by analysis of their low-molecular weight acidolysis products, and it is this application of acidolysis that is the subject of the current presentation Routine analytical procedures have been developed only for monomeric acidolysis products Therefore, analysis of such compounds is the primary concern in this section Analysis of dimeric acidolysis products is, however, of great value for the characterization of lignins and is treated under a separate heading (Sect 6 16)... [Pg.289]

Hydrolysis of lignin in acidic and basic media has received attention due to the rather few and simple degradation products obtained. Acid-catalyzed hydrolysis reactions applied to isolated lignin have been studied by a number of workers. Lundquist (1), for example, subjected Bjorkman lignin to acidolysis and obtained significant yields of monomeric products. A review of the work prior to 1971 has been made by Wallis (2). [Pg.234]

If a reaction mixture obtained after 4 hours acidolysis of Bjorkman lignin (spruce), after neutralization and removal of the polymeric material, were filtered through a Sephadex G 25 column, the elution curve (Figure 5) exhibited three peaks (26). The effluent fractions corresponding to peaks A and B were subjected to further fractionation by chromatography on silica gel columns. We found that fraction A contained only monomeric products while fraction B was a mixture of dimeric products (Figures 6 and 7). [Pg.40]

Note 5 A kinetic study of the recovery of main monomeric products in the thioacidolysis of soluble lignin and unsoluble wood or straw samples has revealed that, between 2 and 6h, the yields are remarkably constant when compared to those reported for acidolysis (Gellerstedt et al 1984, Lapierre 1986) With prolonged reaction time (24h), product yields decrease slightly... [Pg.339]

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,... [Pg.347]


See other pages where Monomeric lignin, acidolysis products is mentioned: [Pg.40]    [Pg.290]    [Pg.160]    [Pg.297]    [Pg.72]    [Pg.462]    [Pg.141]    [Pg.35]    [Pg.349]    [Pg.4243]   
See also in sourсe #XX -- [ Pg.27 ]




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Acidolysis

Lignin production

Lignin products

Monomeric

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