Crown Zellerbach Corporation

William G Whalley

John S Fujii

Fred L Schmidt

Lignocellulose is treated with an alkaline pretreatment liquor containing anthraquinone or other pretreatment agent in a continuous process in which the lignocellulose and pretreatment liquor flow countercurrently. The pretreatment agent is substantially soluble in the pretreatment liquor introduced into the pretreatment zone and is substantially insoluble in the pretreatment liquor withdrawn from the pretreatment zone, with the result that the pretreatment agent is effectively recycled within the pretreatment zone.

Continuous countercurrent pretreatment of lignocellulose with

By pretreating lignocellulose with an alkaline pretreatment liquor containing anthraquinone or a related compound, prior to alkaline digestion, a higher yield of pulp having a lower lignin content can be produced using less alkali. The pretreatment step is carried out under conditions that ensure survival of at least 50% of the anthraquinone or related compound in the pretreatment liquor, which is separated from the pretreated lignocellulose and reused to pretreat other lignocellulose.

Pretreatment of lignocellulose with anthraquinone prior to pulping

A selective process for producing mercaptophenols is achieved by reducing the polysulfides which result from contacting phenols with sulfur chloride in a polar solvent reaction medium including a hydrogen chloride promoter, wherein the concentration of phenols is relatively dilute. The process selectivity promotes the sulfurization of phenols to polysulfides which are reducible to mercaptophenols.

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Vancouver, WA, United States of America

William G Whalley