Pyrolysis studies of organic oxygenates

Pyrolysis gasification reactivities of primary tar and char fractions from cellulose and lignin as studied with a closed ampoule reactor

“…2): 31.7 wt% (50 s) to 27.7 wt% (120 s). Conversion of the guaiacyl-type aromatic ring to o-cresol (1-hydroxy-2-methylphenyl)-and catechol (1,2-dihydroxyphenyl)-types during pyrolysis is reported in the literature [27][28][29][30][31]. The secondary char formation also progressed in this period (50-60 s).…”

“…1 H NMR signals at 9-10.5 ppm (50 s, Fig. 4), which were assigned to the aldehyde protons, disappeared at 60 s. This decarbonylation is considered to be a reason for the enhanced formation of CO. Decarbonylation of the aromatic aldehydes would proceed as indicated in the literature [30,31]. Hydrogen-abstraction from aldehyde by the radical species formed through the O-CH 3 homolysis may activate the decarbonylation reaction.…”

Secondary reactions of lignin-derived primary tar components

“…The decarbonylation would proceed by the Habstraction from the aldehyde-H (Fig. 12) [19]. This mechanism also suggests that the aldehyde group acts as a H-donor to the radical species.…”

“…They also have indicated that the catechol-and o-cresol-type products are produced through the O-CH 3 cleavage in the guaiacol-type aromatic rings. Furthermore, the molecular mechanism of the rearrangement of guaiacol to o-cresol has been discussed in the literature [17][18][19][20]. Thus, the change in the substitution pattern of the aromatic nuclei during pyrolysis is well documented at relatively low pyrolysis temperature.…”

“…As for the primary products from softwood lignin, various guaiacol-type compounds with unsaturated side-chains have been reported, which include coniferyl alcohol, coniferyl aldehyde, isoeugenol, stilbene, vinyl guaiacol and so on [8][9][10][11]13,[15][16][17][18][19][20][21][22]. From the model dimer studies, coniferyl alcohol and vinyl ether have been reported as the major pyrolytic products from the b-ether-type dimers [8][9][10][11]13] through the C b -O bond homolysis (via quinone methide intermediate in phenolic form) and the C g -elimination as formaldehyde, respectively.…”