Acid extraction of the alkaline wood pulps (kraft or soda/AO) before or during bleaching reason and opportunity
1993
Marechal, A.
The decreases in kappa number of an unbleached alkaline hardwood pulp of carpinus betulus when performing dilute H2SO4 hydrolysis at about 100 degrees C, either after or before oxygen bleaching are the same. The main parameters of this acid hydrolysis are specified by studying the acidification of unbleached alkaline pulp suspensions at room temperature, and the extraction kinetics at temperatures in the range of 88-110 degrees C by following UV absorbance of the hydrolysis liquors. Among the dissolved products in the liquors 2-furancarboxylic acid has been identified. This acid results probably from the degradation in the acid medium of compounds present in the unbleached alkaline pulp, which are not oxidized by oxygen in the alkaline medium.
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