Chemiluminescence related to degradation of thermally oxidized pullulans. Comparison with cellulose and dextran

The degradation of pullulan, cellulose and dextran in the presence of oxygen was examined by chemiluminescence and by size-exclusion chromatography (SEC) methods. While 1,4-α glycosidic bonds in pullulan are split thermally only with a slight effect of oxygen, thermolysis of 1,4-β bonds in cellulose and 1,6-α bonds in dextran is preceded by free radical oxidation of carbon 6 of glucopyranose unit with formation of carboxyl groups and water contributing to the subsequent induced degradation of polysaccharide. MgO which remains in polysaccharide after its impregnation by methoxy magnesium methyl carbonate (MMMC) promotes the reaction of terminal semiacetal groups and/or hydroperoxides which has considerably higher quantum yield of light emission.