Ease of delignification assessment of wood from different Eucalyptus species by pyrolysis (TMAH)-GC/MS and CP/MAS 13C-NMR spectrometry

Flash-pyrolysis in the presence of tetramethylammonium hydroxide (TMAH) of woods from different species of Eucalyptus yields series of guaiacyl-type (G) and syringyl-type (S) units in slightly but characteristically different relative proportions. Such differences have been used to suggest a fine and appropriate index of the ease of delignification of the different Eucalyptus species when pulped by the Kraft process. The pyrolytic data were in agreement with those obtained from CP/MAS C-13-NMR spectra of the woods. On the other hand, the various eucalypt woods showed additional differences in their pyrolytic patterns regarding the relative amounts and structure of the high molecular weight aromatic compounds arising from the pyrolysis of polyphenolic wood constituents, which might be used as a basis for chemotaxonomic differentiation of the origin of the woods. (C) 1999 Elsevier Science B.V. All rights reserved.