EXTRACTION OF A LIGNIN FRACTION FROM MAPLE WOOD BY LIQUID AMMONIA

Abstract

Solvent-extracted maple wood meal when re-extracted with nearly anhydrous liquid ammonia at room temperature (about 150 p.s.i.) lost most of its acetyl groups as 4% of acetamide, 0.9% of a polyuronide, and about 1% of lignin. When fractionated, the latter yielded half its weight as subfractions that were nearly uniform in composition and whose cryoscopic molecular weights in dioxane were all near 1000. If the sample was indeed homogeneous, the corresponding molecular formula, C42H33O10(OH)5(OCH3)7, suggested that this fraction was chemically less condensed than the bulk of the lignin in the wood. The behavior of the fraction toward methanolysis, toward oxidation with periodate, and in a sulphite cook is described.