On Hydrotropic Cooking (II)

An Approach to Some Powerfull Hydrotropic Reagents

Abstract

Aqueous aminobenzene sulfonate solutions, such as sodium sulfanilate and sodium metanilate, were found to be efficient delignifying agents for beech wood. Factors affecting the degree of delignification, such as liquor concentration and cooking time, were studied. With wood meals, 93-95% of the original wood lignin could be removed after 2 hr at 170°C in 30% aqueous solution of sodium aminobenzene sulfonates at an initial pH of 9.5. It was found that at a pulping yield of 46% the chemical properties of the pulp after new hydrotropic cooking was superior to that of the conventional hydrotropic digestion. A comparison of the analytical figures and the gel-chromatogram of the new hydrotropic lignins with those of the lignins recovered from the usual hydrotropic cooking liquors showed that the occurrence of the bulk delignification reaction followed by a prior extended depolymerisation would also seem probable.