Chemicals Generated During Oxygen-Organosolv Pulping of Wood

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Abstract
In this paper, we have characterized the black liquors from oxygen-organosolv pulping of Eucalyptus globulus wood in ethanol/water solutions (50:50, V/V) and acetic acid/water solutions (80:20, V/V). After pulp separation, the organic solvent has been distilled and recycled; the precipitated lignin has been recovered by filtration. The degradation products in solution have been easily separated by simple extraction techniques. Five main groups of compounds have been isolated: solid lignin (11–12% o.d.w.), sugars (10–17% o.d.w.), aliphatic acids (12,5%), aromatic acids (2% o.d.w.) and low molecular weight phenols (1% o.d.w.). Most of these compounds were identified by HPLC and GC. Solid lignins have been analyzed by FTIR and 13C NMR spectroscopy. It has been çoncluded that oxygen-organosolv pulping process can be a new and interesting way for pulp preparation with little pollution and possibility of total biomass recovery; alternatively, it can be used for the fractionation and valorization of the components of lignocellulosics, including agriculture residues.