Cellobiose alkaline degradation

Malinen, R., and Sjostrom, E. (1972). Studies on the reactions of carbohydrates during oxygen bleaching. Part I. Oxidative alkaline degradation of cellobiose. Pap. Puu 54, 451 -468. 

It has long been known that D-glucose substituted at C4, as in the disaccharides lactose, cellobiose, and maltose (see page 48), is particularly suitable for the preparation of a -D-isosaccharinic acid through treatment with lime-water. Since this acid is only a minor product of the action of alkali on unsubstituted D-glucose, the presence of a substituent at C4 must preferentially direct the alkaline degradation to the isosaccharinic structure. 

During the alkaline degradation of cellulose and cellobiose, a yellow chromo-phore is formed whose spectral properties are dependent on pH e.g. Am 290 nm at pH 12 was shifted to 256 nm at pH 6 for both hydrocellulose and cellobiose. It is suggested that the chromophore is a jS-hydroxy-a-enone which, at acid pH values, tautomerizes to an aliphatic jS-diketone. It was concluded that the chromophore is a minor product since the molar absorption coefficients of such compounds are very large (> 1 x 10 ) and the apparent molar absorption coefficient for hydrocellulose was only about 900. 

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