Studies on the lignin of Eucalyptus regnans F. Muell. VII. The acid hydrolysis of ethanyol lignin-A

Abstract

Ethanol lignin-A from the ethanolysis of Eucalyptus regnans P. Muell. has been hydrolysed with dilute hydrochloric acid with the object of ascertaining whether the combined ethoxyl is present as an acetal or as ether. Hydrolysis with 12 per cent. hydrochloric acid was found to split off one ethoxyl group, while hydrolysis with 20 per cent. acid brought about complete de-ethylation. The de-ethylated ethanol lignin-A contained one carbonyl group less and two hydroxyl groups more than the original ethanol lignin-A. These results lend no support to the hypothesis that alcohol lignins are acetals, and favour the theory that the combined alkoxyl is probably present as ether.