Delignification of hardwoods by autohydrolysis and extraction.

Abstract

Autohydrolysis of Eucalyptus saligna, Poplar tremuloides, and fast-growing poplar chips at 175 to 220/sup 0/ induced lignin (I) solubility in dioxane-H/sub 2/O mixture (9:1) or 1% NaOH. The I solubility exhibited a maximum characteristic of autohydrolysis temperature, and maximum delignification was achieved in a narrow time range at each temperature of autohydrolysis. Longer autohydrolysis reduced the I solubility, at the point of maximum I solubility, autohydrolysis aspen chip were readily defiberized, even without the subsequent extraction. E. saligna and fast-growing poplar also gave similar results.