Comparative Studies of Hemicelluloses Solubilized during the Treatments of Maize Stems with Peroxymonosulfuric Acid, Peroxyformic Acid, Peracetic Acid, and Hydrogen Peroxide. Part 2. Spectroscopic and Thermal Characterizations

Abstract

Ten hemicellulosic preparations, obtained by treatments of the water-extracted maize stems with peroxymonosulfuric acid, peroxyformic acid, peracetic acid, and 2 % hydrogen peroxide under the conditions given, respectively, were investigated by gel permeation chromatography and spectroscopic techniques such as Fourier transform infrared and carbon-13 nuclear magnetic resonance. Under an optimum extracting condition (2 % H 2 O 2 , 45°C, 12 h, pH 11.5-12.0), the hemicelluloses obtained represented 63.3-64.7 % of the original hemicelluloses and had high weight-average molar mass between 69060 and 54740 g mol -1 . The most obvious feature was found that the alkaline peroxide treatment of the stems under the conditions used did not affect the overall structure of the hemicelluloses. The thermal stability of the hemicelluloses was found to increase slightly with increasing molar mass. All the hemicellulosic preparations were, however, to varying degree thermally unstable at temperature above 180°C. KeywordsMaize stems Hemicelluloses Hydrogen peroxide Molar mass FT-IR spectra 13 C-NMR spectrum Thermal stability 492 Brought to you by |

Comparative characterization of degraded and non-degradative hemicelluloses from barley straw and maize stems: Composition, structure, and thermal properties

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