Reaction of Sodium Chlorite with Various Polysaccharides. Rate Studies and Aldehyde Group Determinations

Abstract

Aldehyde contents and degree of polymerization values of polysaccharides were calculated from chlorite results obtained under various conditions and using the corresponding stoichiometric ratios determined for substances of low molecular weight. The polysaccharides were three native dextrans, a series of hydrolyzed dextrans including clinical dextran, a periodate dextran, a series of araban fractions, and starches including pea, wheat, and rice amylopectin, and a series of periodate cornstarch products. The results with various chlorite procedures were self-consistent and agreed well with those of other chemical methods, and fairly well with those of light-scattering for fractionated polymers. For native dextrans, where no agreement was to b e expected, the large divergence demonstrated inhomogeneity of substance. Agreement with osmotic pressure results was fair to poor. HE oxidation by sodium chlorite in T phosphate buffer of a variety of mono-and disaccharides and benzaldehyde was recently studied (12) with respect to the chlorite-aldehyde stoichiometry as affected by buffer strength, reaction rate, and concentration of reactants. Various experimental conditions employing sodium chlorite were dweloped for application t o the determination of aldehyde groups in polysaccharides.This communication describes the study of the rates of oxidation under those conditions and others of a series of periodate cornstarches; of a series of dextrans, including native, periodate, clinical, and more extensively acidhydrolyzed; and of a series of arabans.

Degradation of cellulose polymorphs into glucose by HCl gas with simultaneous suppression of oxidative discoloration

“…7b). The impediment of NaClO 2 on cellulose hydrolysis is likely due to unstable chlorine intermediates that react with chlorite and HCl to a varying extent and have been shown to influence the reaction efficacy of NaClO 2 with model substances (Launer & Tomimatsu, 1959). Because 2 wt% appeared to be the threshold value for NaClO 2 addition to significantly interfere with the hydrolysis, yet it managed to suppress the humin formation for several days on end (Fig.…”

Polysaccharides

“…They are successfully used for the isolation of pectolytic enzymes [136], [137]. Pectins are readily degraded by oxidants [138] except for chlorite and chlorine dioxide, which can selectively oxidize aldehyde groups at the reducing chain end [139].…”

“…Pectins are readily degraded by oxidants [138] except for chlorite and chlorine dioxide which can selectively oxidize aldehyde groups at the reducing chain end [139].…”

Alkali Sensitivity of Polysaccharides: Periodate Starches, Periodate Dextran and a Polygalacturonide1

“…Solutions of the periodated materials were more difficult to prepare and were made as previously described. 20 Portions thereof (containing 3.6 mg., dry basis, of periodate dextran, as an example, and more for substances of lower aldehyde content) were then added to carbonate-bicarbonate buffers, sodium carbonate or to sodium hydroxide solutions to give the following systems: Most studies were made in the buffer of the Blom and Rested28 reagent (referred to in the forthcoming study as the "Carbonateiodine" reagent) but without iodine, 0.133M in sodium carbonate and 0.033Af in sodium bicarbonate giving pH 10.2. Some experiments were conducted at pH 9.3 in a buffer, 0.02M sodium carbonate and 0.08M sodium bicarbonate, some at pH 10.5 in 0.05 7 sodium carbonate, and a few at pH 11.9 in 0.04 sodium hydroxide (the final alkalinity of the Willstátter-Schudel reagent).…”