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Hydrol lignins

Hydrol lignin A was crudely fractionated by repeatedly precipitating a chloroform solution into ether this yielded a low molecular weight ether-soluble fraction (65%) and a high molecular weight ether-insoluble fraction (35%). [Pg.240]

Chemical Shift Values for Hydrol Lignins. Lignins isolated by hydrogenolysis contain structural features not present initially, and it was necessary to determine the values for chemical shifts for the new types of protons. This was done using 8 values from the literature (/, 2, 5) from spectra of model compounds prepared in this study of the guaiacyl and syringyl type, substituted with Ci, C2, and C3 hydrocarbon side chains,... [Pg.240]

C2 and C3 primary alcohol side chains guaiacyl type models substituted in the C6 position with reduced carbon side chains and acetylated derivatives of these models from spectra cf the several hydrol lignin preparations. [Pg.241]

Hydrol Lignin A Acetylated Hydrol Lignin B Acetylated Ether Insoluble A Acetylated... [Pg.244]

Retention Timey min. Acid-Catalyzed Hydrol Lignin Base-Catalyzed Hydrol Lignin... [Pg.247]

The ether-soluble fraction from hydrol lignin A was analyzed by NMR spectra and by gas chromatography. The NMR spectra is nearly identical with that of dihydroconiferyl alcohol and dihydrosinapyl alcohol, which were shown to be present in large amounts by gas chromatography. [Pg.249]

The structure of hydrol lignin has been examined by NMR spectroscopy. Tables of 8 values for types of protons found in hydrol lignin have been established, and 8 values for various types of aromatic ring substitution patterns have been clarified. [Pg.249]

The relative amounts of uncondensed guaiacyl, condensed guaiacyl, and syringyl nuclei in hydrol lignin preparations have been estimated at 43%, 23%, and 34% respectively for an acid-catalyzed product and 30%, 22%, and 48% for a base-catalyzed product. [Pg.249]

Ether-insoluble hydrol lignin from the acid-catalyzed product seems to be a highly condensed guaiacyl type of preparation which has not been severely degraded during the isolation process. [Pg.249]

Granath M, Schuerch C (1953) Preliminary separation of maple hydrol lignin J Am Chem Soc 75 707-709... [Pg.366]

See other pages where Hydrol lignins is mentioned: [Pg.239]    [Pg.240]    [Pg.240]    [Pg.241]    [Pg.241]    [Pg.242]    [Pg.243]    [Pg.243]    [Pg.244]    [Pg.244]    [Pg.244]    [Pg.246]    [Pg.246]    [Pg.248]    [Pg.248]    [Pg.248]    [Pg.248]    [Pg.249]   
See also in sourсe #XX -- [ Pg.227 , Pg.228 ]



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