Studies on Lignin and Related Compounds. LXVI. The Ethanolysis of Maple Wood

Abstract

Vol. 65insoluble product not being obtained by re-ethanolysis of 3 mafile ether-soluble lignin.As in the case of maple lignin, the water-soluble spruce lignin (G') could be separated into a petroleum etherinsoluble (J') and a petroleum ether-soluble (K') fraction and the latter separated further into a bisulfite (L'), an acid (M'), an alkali (N') and a neutral (0') fraction.From the bisulfite and alkali fractions 1-(4-hydroxy-3methoxyphenyl)-1,2-propanedione and Z-ethoxy-l-(4-hydroxy-3-methoxyphenyl)-l-propanone, respectively, were isolated and identified by the usual methods.3 Thus re-ethanolysis of both spruce and maple ethanol lignin fractions yields the same products as isolated by use of the standard wood ethanolysis procedure and there would seem to be no doubt but that the extraction of lignin by the action of ethanolic hydrogen chloride involves the previously-discussed' concurrent polymerization-depolymerization changes. The amount of polymerization is evidently greater, and the depolymerization less, in spruce (a gymnosperm) than in maple (an angiospermi. The fact that l-(4-hydroxy-3-methoxyphenyl)-l,2-propanedione and 2-ethoxy-l-(4-hydroxy-3-methoxyphenyl)-1-propanone from spruce wood and these two derivatives together with their 4-hydroxy-3,5-dimethoxyphenyl honiologs from maple wood are the only, as yet, isolable cleavage products of each ethanol lignin fraction indicates that they are either primary cleavage products or, as now seems ____-___1180 &MARSHALL KULKA AND HAROLD HIEBERT Vol. 65

Zur Bestimmung der „Hibbert-Körper“

“…4 Da beide Möglichkeiten nur sehr mühevoll experimentell zugänglich sind, lag es nahe, nach Relativ-Auswertungen zu suchen, die sich aus ähnlichen Gründen, z. 140° C (0.5% HC1) und 140° C (3% HC1) erhaltenen Äthanolysaten durch und bekamen für jedes Papierchromatogramm die in Abb.…”

Solvolytic liquefaction of wood under mild conditions

“…Hibbert et al(30) andSarkanen and Schuerch (31) have depolymerized spruce lignin by ethanolysis, using a mixture of ethanol and chloroform as solvent and a small amount of hydrogen chloride as catalyst. They discovered that extensive bond scissioning occurred if ethanolysis was carried out at high temperature (150°C).…”