Isolation of lignin from spruce by acidolysis in dioxane

Summary Acidolysis of spruce wood (Picea abies) corresponded to a pseudo-first order reaction mechanism. While anhydrous methanolis a better medium for wood acidolysis than anhydrous dioxane, after addition of 10% water dioxane became about twice as effective as methanol. The results are discussed in terms of acidity functions (H), solubility parameters and condensation effects. Infrared spectra of dioxane lignins showed a similar re-arrangement of side chain carboxyl groups from to position, as was observed previously during acidolysis in methanol.