Sweetening of Wood

Sweetening of wood to glucose is not economic at present. Previously, the resulting glucose was not recovered as such, but fermented to alcohol. But 49% of the carbon is lost as CO2 in this process. The conversion of glucose to fructose, sorbose, glycerine, or hydroxymethyl furfural is also not economic at present (see Table 24-15). 

In the sweetening of wood, the wood is hydrolyzed at 140-180°C and 6-9 bar with 3-6% sulfuric or hydrochloric acid with 1-2% added SO2. The resulting glucose is not generally recovered as such, but is converted into alcohol. About 10 dm of alcohol is obtained from 100 kg of wood, i.e., 17% of the formula yield. Furfurol, aliphatic ketones, and aldehydes occur as by-products. 

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