Sulfite pentosans

Fermentation of Sulfite Waste Liquor. The sulfurous acid used in the sulfite pulping liquor causes hydrolysis of the more easily hydrolyzable components of wood, especially the pentosans in the hemicellulose. About 35 percent of the potentially fermentable sugars in the wood are hydrolyzed. However,... 

Examples of the diminution of the pentosan of wood pulps by alkaline purification may be taken from the work of Richter. In a series of papers dealing chiefly with the pulping of hardwoods, Richter showed that either hot, dilute, sodium hydroxide or more concentrated sodium hydroxide at ordinary temperatures removes a substantial part of the pentosan from sulfite pulps. Some of Richter s data are shown in Table XVI. 

Removal of Pentosans from Unbleached, Sulfite Pulps ... 

The reaction requires a temperature in the order of 140 °C, and as it is acid, pentosan in the wood is hydrolyzed to pentose, and some of this pentose is dehydrated to furfural. Against this background, there has been a persisting interest in converting the pentose of sulfite liquor to furfural, and to recover the furfural already existing in the liquor. 

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