Uronic acids alkaline degradation

The formation of 4,5-unsaturated uronic acid residues by enzymic or alkaline degradation of polysaccharides containing uronic acids has been the object of many investigations.214... 

The consumption of effective alkali in a kraft cook corresponds to about 150 kilogram sodium hydroxide per ton of wood. As a result of the alkaline degradation of polysaccharides, about 1.6 equivalents of acids are formed for every monosaccharide unit peeled from the chain. Of the charged alkali, 60-70% is required for the neutralization of these hydroxy acids, while the rest is consumed to neutralize uronic and acetic acids (about 10% of alkali) and degradation products of lignin (25-30% of alkali). 

D-glucopyranosyl uronic acid residues.Further examination of the polysaccharide (9) by alkaline degradation, followed by methylation, revealed that the D-glucuronic acid residues are located on D-mannosyi residues already substituted with a D-xylosyl residue. The capsular polysaccharide of C. neoformans serotype D is less highly branched, but with many structural similarities to (10). ... 

Details of a number of established chemical methods used in determining various aspects of the fine structures of polysaccharides-for example, the specific degradation of polysaccharides containing uronic acid residues by base-catalysed elimination, the location of acyl substituents, and the distribution of singleunit side-chains of D-galactose in galactomannans by alkaline hydrolysis of 6-deoxy-6-(4-tolylsulphonyl)hexopyranosides -are reported in the latest volume in the series Methods in Carbohydrate Chemistry . 

---