Lignin beech

Figure 25-9 Proposed structure of beech lignin. There are 25 different C9 units, of which several can, to some extent, be replaced by the three dimeric units in brackets. Redrawn from Nimz,194 p. 317.

Dissolution of almost 40% of powdered beechwood in this way 20) suggests that the benzyl aryl ether content of beech lignin is much higher than that of spruce lignin. 

Both Adler and Freudenberg have constructed structural schemes for spruce lignin and Nimz for beech lignin in which the main units and linkage types are represented in their approximate proportions. The scheme by Adler is depicted in Fig. 4-9. 

J Softwood (spruce) lignin. b Hardwood (beech) lignin. 

Musha Y, Goring DAI (1975) Distribution of synngyl and guaiacyl moieties in hardwoods as indicated by ultraviolet microscopy Wood Sci Technol 9 45-58 Nimz HH (1974) Beech lignin - proposal of a constitutional scheme Angew Chem Int Ed 13 313-321... 

H Nimz. Beech lignin— Proposal of a constitntional scheme. Angew Chem Intemat Edit 13 313-321, 1974. 

Nimz H. (1974) Beech lignin-proposal of a constitutional scheme. Angew. Chem., Int. Ed. Engl. 13, 313—21. 

Nimz H., Chemistry of potential chromophoric groups in beech lignin, Tappi, 56(5), 1973, 124-126. 

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