Paper partition chromatographic study of the products of the chlorine oxidation of D-glucose and Methyl-beta-D-glucoside at pH "0" and pH 4.6

Thesis (M.A.)--Boston UniversityD-Glucose and methyl-beta-D-glucoside were oxidized at pH "0" by continuously passing chlorine gas into aqueous solutions of carbohydrates for fourteen days at room temperature. The products of these oxidations were investigated after lyophilization of the reaction mixtures by paper partition chromatographic analysis with the solvent system n-butanol-acetic acid-water, 4: 1: 5, and using various spray reagents. These two carbohydrates, D-glucose and methyl-beta-D-glucoside, were also oxidized for twenty-four hours with chlorine water at pH 4.6 in 0.3 molar acetate buffer at 35.7°C. A large excess of carbohydrate with respect to oxidant was used in these oxidations. The results obtained are listed in Table XXVI. D-Glucaric and 2-ketogluconic acids were shown not to present these oxidations even though their presence were reported by other investigators using similar oxidation procedures (21,35a). The conditions of the oxidation of methyl-beta-D-glucoside at pH 4.6 were shown to be too mild to produce oxidative changes, in contradiction to the work of Henderson (35a) who, using similar oxidative conditions, reported that the glucoside underwent oxidation to produce a number of oxidation products. No temperature dependence of Rf or Rg was noted, even though such temperature dependence was previously reported. A large excess of D-glucose was shown not to affect the Rf values of compounds present in smaller quantities. A method was devised whereby an acidic or alkaline compound and a reducing compound may be detected on a single chromatogram: the so-called "double spraying" technique. It was shown experimentally that carbohydrates and sugar acids are not affected by storage in water solution under refrigeration for periods of over six months. The presence of sodium acetate and an acidic impurity in the sodium acetate used were shown on chromatograms of the oxidation experiments carried out in acetate buffers. Recent advances in the chemistry of the halogen oxidation of carbohydrates are reported

Kenyon Collegian - September 24, 2020

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Gli immigrati e le loro associazioni in Lombardia. Un aggiornamento del monitoraggio

Il testo presenta i risultati dell'ultimo aggiornamento della banca dati delle associazioni di stranieri attive in Lombardia realizzato dall'Osservatorio Regionale per l'integrazione e la multietnicit\ue

Student Life, October 8, 1909, Vol. 8, No. 4

Weekly student newspaper of Utah State University in Logan.https://digitalcommons.usu.edu/newspapers/1609/thumbnail.jp

April 1892

April 1892 issue of The Student

The Free Press Vol. 48, Issue No. 6, 10-24-2016

Suicide 101: What you need to know -- Triggered by Trump -- How addiction correlates with mental illness -- USM community works to dispel stigma surrounding mental illness -- How hypnotism can offer you a deeper understanding of yourselfhttps://digitalcommons.usm.maine.edu/free_press/1169/thumbnail.jp