The Influence of Pulping Conditions on the Structure of Acetosolv Eucalyptus Lignins

Abstract

Abstract Acetosolv lignins obtained under a variety of pulping conditions as regards acetic acid concentration, catalyst concentration, temperature and pulping time were characterized structurally by elemental analysis, FTIR and 1H and 13C NMR spectroscopy, and determination of methoxyl group content. Increasing catalyst concentration and pulping time favours both the dissolution of lignin (by cleavage of α and β-O-4 bonds) and the occurrence of condensation reactions. Increasing temperature favours the degradation of syringyl units more than of guaiacyl units.