Method for the preparation of xylose solutions

DETAILED DESCRIPTION What is claimed is: 1.
A method for the preparation of xylose solutions from oat husks which comprises: a.
hydrolyzing oat husks with a solution of alkali metal hydroxide to provide oat husks from which the chemically bound acetic acid originally present therein has been substantially completely removed, and a solution of acetic acid, provided, that a quantity of not less than one mole, and not more than two moles, of said solution of alkali metal hydroxide is used per mole of acetic acid originally present in the oat husks; b.
recovering the oat husks from which the chemically bound acetic acid has been substantially removed; and c.
hydrolyzing the oat husks of step (b) with a mineral acid to provide a solid residue containing lignin and an acidic solution of D-(+)-xylose.
2.
The method of claim 1 wherein the D-(+)-xylose present in the acidic solution of step (c) is recovered therefrom in substantially pure form.
3.
The method of claim 1 wherein hydrolysis step (a) is carried out with a solution containing from 1.
1 to 1.
2 moles of alkali metal hydroxide per mole of acetic acid orginally present in the oat husks.
4.
The method of claim 1 wherein hydrolysis step (a) is carried out with a solution of sodium hydroxide, potassium hydroxide or combination thereof.




Description:
BACKGROUND OF THE INVENTION 1.
Field of the Invention This invention relates to methods for hydrolyzing oat husks to provide D-(+)-xylose.
2.
Description of the Prior Art D-(+)-xylose and its hydrogenation product, xylitol, are of considerable industrial significance.
For example, xylose can be employed for various purposes in the foodstuffs industry, while xylitol has proved to be a very good sweetener for diabetics.
Varieties of deciduous timber, such as beech and chestnut, are used almost exclusively as the starting material for the industrial manufacture of xylose.
The yields are about 10-12% (compare, for example, German Pat.
No.
912,440).
It is a significant disadvantage of these processes that the wood material which remains, so-called cellolignin, has hitherto been incapable of practicable industrial utilization and that the process mentioned only gives moderate yields of xylose