19.5.2020 Oxidative Reactions of Cellulose under Alkaline Conditions (Adibi Larijani)

The purpose of investigation in Amir Adibi Larijani's dissertation was to elucidate the influence of oxygen, gas pressure, and temperature on the oxidative degradation of cellulose and the formation of degradation products under alkaline conditions. This kind of degradation is of importance in many industrial applications, including, for example, the viscose process for making rayon fibers needed in the clothing industry.
Published
19.5.2020

In order to simplify the reaction system the experiments were carried out with the cellulose model compound cellobiose being a repeating unit of cellulose only with two glucose molecules. Reaction products were determined and identified as their volatile derivatives by gas chromatography.

During the experimental work, it was identified about 40 degradation products, of which about 30 were also quantitatively evaluated and the products were divided into those formed under oxidative and non-oxidative conditions. The principal degradation products were glucose as well as glycolic, lactic, glyceric, 3,4-dihydroxybutanoic, 3-deoxy-pentonic, and glucoisosaccharinic acids.

In general, an inhibiting character of oxygen upon cellobiose degradation was observed. Especially, at lower temperatures an increase in oxygen pressure caused the formation of non-oxidative degradation products in trace amounts. The formation of oxidative degradation products took primarily place kinetically and non-oxidative degradation products thermodynamically. Additionally, the kinetic calculations revealed that at room temperature the degradation of cellobiose proceeded four times slower in air than in one bar nitrogen; the activation energies were 122 kJ/mol and 79 kJ/mol, respectively. Based on the obtained results a new ionic reaction mechanism for the overall phenomenon was postulated.

The disseration is published in JYU Dissertations series, number 217, Jyväskylä , 2020. 
ISBN 978-951-39-8157-0 (PDF) URN:ISBN:978-951-39-8157-0 ISSN 2489-9003

Link to publication

For further information:
Amir Adibi Larijani, amir.adibi@hotmail.de

M.Sc. Amir Adibi Larijani defends his doctoral dissertation in Chemistry "Oxidative reactions of cellulose under alkaline conditions" on Tuesday 19 May 2020 at the Ä¢¹½Ö±²¥ starting at 12. Opponent Professor is Herbert Sixta from Aalto University and Custos Professor is Emeritus Raimo Alén from the Ä¢¹½Ö±²¥. The doctoral dissertation is held in English.

The dissertation is held online. Link to the Zoom Webinar: 
Meeting ID: 652 3383 9521