Formation of benzenediols upon electron-beam distillation of lignin mixtures with alkanes

Thermopolymerization inhibitors generated via radiolysis of lignin

“…Guaiacol and creosol domination agrees with the fact that coniferous lignin represents a combination mainly of guaiacylpropane base units, i.e., coniferyl alcohol serves as the main monolignol [10]. The total radiation-chemical yield of tar components is about 30 µmol/J that testifies to the chain mechanism of their formation [11][12][13].…”

“…7 Composition of the benzenediols series in the tar formed via three modes of dry distillation. DD conventional dry distillation of lignin, EBD radiation-assisted dry distillation of lignin, EBDW radiation-assisted dry distillation of lignin/wax mixture radical and a fragment of the macromolecule with a protonated polar group should be considered as a key reaction scheme of the primary radiolytic transformations of lignin [11][12][13][14].…”

“…The conversion of the radical anion into the H adduct is simplified due to the presence of acids among the products of lignin radiolysis (for example, acetic acid). Structurally similar adducts result from the addition of H atoms to the aromatic units of lignin [12][13][14]: Typically, the aromatic radical is thermally degraded by cleavage of the bond in the β-position relative to the benzene ring [11][12][13]. The methoxy O-CH 3 bond is in the β-position.…”

“…Radiolysis of wax can be considered as a source of H and CH 3 radicals, whereas aromatic units of lignin serve as effective scavenger of these radicals [12,13]. Correspondingly, the cleavage of the weak O-CH 3 bond of the methoxy group is the most probable reaction path of the high-temperature conversion of the H and CH 3 adduct:…”

“…In particular, they can be the direct precursors of 3-methylcatechol and 3,4-dimethylcatechol, respectively. A possible reaction path in the propagation of chain fragmentation is the high-temperature reproduction of methyl radicals [12,13].…”