Influence of the base nature on the lignin reactivity and oxidation selectivity during oxygen delignification of Picea excelsa

The influence of the base's nature on the kinetics of lignin and polysaccharides degradation of Picea excelsa wood during oxygen delignification was investigated using four different bases, namely NaOH, Na(2)CO(3), NaHCO(3) and NH(4)OH. A linear relationship between the initial rate of delignification and the pH of the media was found. The kinetics of delignification, as well as that of carbohydrate degradation, carbon dioxide formation and oxygen consumption were studied, and appeared to be in good agreement with the kinetic studies already reported in, literature. The radical chain mechanism of oxygen delignification in all alkaline media applied was confirmed. The base's origin revealed a notable, influence on the selectivity of oxygen delignification.