GB555985A - Improvements in or relating to the manufacture of cellulose - Google Patents

Abstract

555,985. Cellulose. DREYFUS, H. March 11, 1942, No. 3194. [Class 2 (ii)] In the production of cellulose from cellulosecontaining materials, the latter are subjected to the action of an oxidizing agent which acts as a source of free oxygen, or to the action of oxygen itself, in the presence of an organic acid which contains in solution a metal salt which is an oxidation catalyst. The process is applicable to the treatment of wood, straw, or grasses, e.g. ash, oak, elm, poplar, birch, beech, larch, pine, spruce, or fir. The wood or other material is preferably treated in finely divided state, e.g. in the form of sawdust or small chips. The cellulosic material may first be treated with dilute alkali, e.g. by boiling it with a 1 per cent. solution of caustic soda for about one hour. The oxidizing agent may be hydrogen peroxide, sodium peroxide, barium peroxide, oxygen, or air. The organic acid may be a lower fatty acid e.g. acetic, propionic, or butyric acid, and it may be used as a 25-75 per cent. solution in water. The treatment may be carried out at 40-70‹C. The oxidation catalyst may be a salt of cobalt, nickel, iron, chromium, aluminium, or manganese. The treatment oxidizes the lignin of the wood or other material and renders it soluble in dilute alkali. After the oxidation treatment, the material may therefore be boiled with dilute alkali. It may then be treated at ordinary temperature with caustic soda of 9-15 per cent. strength to remove hemicelluloses. The product is of high α-cellulose content and may be used for paper making or for making viscose, cellulose nitrate or acetate, or other cellulose derivative. The Provisional Specification describes also the treatment of the cellulose-containing material with an oxidizing agent such as hydrogen peroxide in the presence of ammonia.