MECHANISMS OF OXIDATIVE DEGRADATION OF CARBOHYDRATES DURING OXYGEN DELIGNIFICATION. II. REACTION OF PHOTOCHEMICALLY GENERATED HYDROXYL RADICALS WITH METHYL β-CELLOBIOSIDE

Abstract

Reactions involving methyl β-cellobioside and several oxygen species were used to investigate cleavage of glycosidic linkages in cellulose by reaction with photochemical hydroxyl radicals. The intent is not to reproduce delignification conditions, but rather to study the specific behavior of carbohydrate models toward hydroxyl radical. Experiments show that hydroxyl radicals are responsible for the degradation of glycosidic linkages in methyl β-cellobioside by substitution reactions displacing cellobiose, D-glucose, methyl β-D-glucoside, and methanol. Once the glycosidic linkages are broken, the reducing carbohydrates undergo a series of reactions forming aldonic acids and lower order aldoses in the same manner as described previously.[1]

ACKNOWLEDGEMENTS

The authors would like to acknowledge the financial support provided by USDA grant 96-934158-3003 and analytical assistance from Johnna Brazier.