AQUEOUS CATALYSED SOLVENT PULPING OF LIGNOCELLULOSE

摘要

High quality and high yield of chemical pulp is obtained by cooking fragments of lignocellulose material at up to 250.degree.C with mixture of alcohol-water in volume ratio between 50:50 to virtually anhydrous methyl alcohol having in solution as primary catalyst between 0.001 to 1.0 moles of chloride, nitrate or sulphate salt of magnesium, calcium or barium and an autocatalytically generated organic acid from 0.0001 to 0.05 Normal; and added strong mineral acid, or weak mineral acid, or organic acid from zero to 0.01 Normal or an acidic metal salt secondary catalyst from zero to 0.01 Molar may be added and aids rapid and early delignification. In addition, pressures substantially higher than normally developed in enclosed spaces of particular solvent compositions used at the particular temperatures aid both delignification and in particular suppression of carbohydrate degradation. Undegraded depolymerized lignin and carbohydrates are separated from said pulp fibers by straining and washing and are recovered separately on reclaiming the cooking solvent.