GB572638A - Improvements in and relating to the treatment of cellulosic material with a view to the production therefrom of glucose - Google Patents

Abstract

In treating cellulose with an acid such as sulphuric acid to produce glucose, an intermediate product described as cellodextrin is first formed and separated and is then hydrolysed to form glucose. The cellulose is stirred or kneaded at room temperature with concentrated sulphuric acid containing an ester of an organic acid and an organic acid both of low boiling point, e.g., a liquid containing 77 per cent. sulphuric acid, 6 per cent. acetic acid, 11 per cent. ethylacetate and 6 per cent. water. Cellodextrin is precipitated by addition of an organic ester such as ethyl acetate and is washed with ethyl acetate. It is dissolved in water, when occluded ethyl acetate separates as an upper layer and is removed, and the solution is heated with dilute sulphuric acid, sufficient of which may already be contained in the solution. Ethyl acetate may be recovered from the residual liquors by distillation in presence of further quantities of acetic acid. Excess of acetic acid is then removed by distillation under reduced pressure and the composition is adjusted for re-use. Amyl acetate may be used in place of ethyl acetate. Preliminary purification of cellulose-containing material may be effected in the case of wood to secure pure cellulose therefrom, and in the case of straw by treatment with dilute acid to hydrolyse hemicellulose, and then with hot alkali, or chlorine and alkali, to remove lignin. Specifications 311,695, [Class 127], 353,028, 376,322, 376,323 and 376,372 are referred to.