The inner bark of Douglas-fir was successively extracted with ethanol-water (4:1 v/v), benzene-ethanol (2:1, v./iv), water, and 0.5% aqueous ammonium oxalate solution. The residue was reacted with acidified sodium chlorite, a commonly used reagent to separate lignin from carbohydrates. In general the reaction dissolves the lignin and leaves the carbohydrates...
