Wood as It Influences Hydrolysis

Wood is composed of two different types of carbohydrate materials, which differ greatly in their ease of hydrolysis. They are hemicellulose, which is easily hydrolyzed, and alpha cellulose, which hydrolyzes slowly. 

Percentage Composition of Easily Hydrolyzable Hemicellvloses in Spruce Holocellulose 

Hemicellulose Upon basis of hydrolyzed material Upon basis of wood 

The more stable carbohydrate constituent of wood is assumed to be almost pure alpha cellulose. This is shown by the fact that 94-96% of the reducing materials, obtained in the later stages of hydrolysis, is fermentable. High temperatures and longer periods of time are required for the hydrolysis of the stable cellulose when dilute acid is used. If strong acid (72% sulfuric, 45% hydrochloric, 85% phosphoric) is used, the cellulose dissolves and then is converted into smaller units. Both of these procedures have been studied by many experimenters. 

The term hydrocellulose has been assigned to the hydrolytic products intermediate between cellulose and n-glucose. When cellulose is subjected to the action of acid for even brief periods, there is a change in its tensile strength, copper number and viscosity. 

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