A NEW RAPID TECHNIQUE FOR THE CHARACTERIZATION OF LIGNIN IN VASCULAR PLANTS - THERMOCHEMOLYSIS WITH TETRAMETHYLAMMONIUM HYDROXIDE (TMAH)

Flash pyrolysis in the presence of tetramethylammonium hydroxide (TMAH ) has been utilized for the characterization of lignin in a gymnosperm (pine), angiosperm (alder), and nonwoody (Juncus effusus L.) vascular plant tissue. The gymnosperm tissue yielded primarily methylated guai acyl derivatives resulting from cleavage of lignin beta-O-4 bonds and subsequent methylation of acidic hydroxy groups. The angiosperm tissue also yielded guaiacyl-type compounds in addition to an analogous suit e of methylated syringyl lignin derivatives. The nonwoody angiosperm y ielded methylated cinnamyl lignin derivatives in addition to methylate d guaiacyl and syringyl compounds. Analysis of alder wood with this te chnique at a low temperature of 310 degrees C has demonstrated that th e dominant reaction with TMAH is mainly a thermally assisted chemolyti c degradation rather than degradation induced by pyrolytic bond cleava ge. Accordingly, we now call the technique TMAH thermochemolysis.