GB353028A - Improvements in the treatment of cellulosic materials - Google Patents

Abstract

Wood and other cellulose materials are saccharified by treatment with an organic acid anhydride and hydrolysing the product, one or more stages of the treatment being so conducted as to degrade the cellulosic material to sugars. Acetic anhydride, butyric anhydride or propionic anhydride may be used and the esterification may be carried out in the presence of sulphuric acid, phosphoric acid, or other mineral acid reagent and the temperature may be 60-90 DEG C. The anhydride may be mixed with acetic acid or benzene, the acetic acid being recovered by extraction with benzene, toluene, petroleum ether, ether, or chlorohydrocarbons or the reaction is carried out in the presence of a solvent for acetic acid so that the cellulose acetate or degraded cellulose acetate is produced in suspension. The hydrolysis may be effected by steam. The cellulose may be purified with an alkaline agent to remove pentosan and then treated with a mineral and/or organic acid such as acetic and sulphuric acid. In one example, cellulose is treated with a dilute alkali then with acetic and sulphuric acid, acetic anhydride is added and the mixture heated with steam. The steam is continued until the product is completely water soluble, after which the sulphuric acid is neutralized by suitable addition of lime. In another example a mixture of acetic, sulphuric, and phosphoric acids is used. The acetylation and the hydrolysis of the product may then be conducted as described in the other example. Specifications 249,173, 263,938, 264,937, 312,098, and 326,515, [all in Class 2 (ii), Cellulose &c.], are referred to.