Effect of urea on cellulose degradation under conditions of alkaline pulping

abstract

The effect of urea on the cellulose degradation under conditions of alkaline pulping has been studied using purified cellulose powder. The increased cellulose yield in the presence of urea was assigned essentially to the carbamation reactions which were confirmed by elemental analysis, UV-resonance Raman and solid-state C-13 nuclear magnetic resonance spectroscopy. The stabilizing effect of urea on the cellulose peeling reactions during heating up period of pulping process was suggested based on kinetic studies and additionally confirmed in model reactions using cellobiose. The reaction products formed in alkaline urea solutions were analysed by tandem electrospray ionization mass spectrometry and the occurrence of Maillard type reactions between reducing end groups of cellobiose and urea were evidenced. Both Maillard type reactions and carbamation of reducing end groups were proposed to be a part of cellulose protection mechanism against peeling under the conditions of alkaline pulping.

keywords

CARBONYL GROUPS; MASS-SPECTROMETRY; HOT ALKALI; KINETICS; OLIGOSACCHARIDES; POLYSACCHARIDES; HYDROCELLULOSE; ADDITIVES; PRODUCTS; WOOD

subject category

Materials Science; Polymer Science

authors

Ershova, O; da Costa, EV; Fernandes, AJS; Domingues, MR; Evtuguin, DV; Sixta, H

our authors

acknowledgements

Authors acknowledge Portuguese Foundation for Science and Technology (FCT) for the financial support of this work within the scope of CICECO grant PEst-C/CTM/LA0011/2011 and TEKES-the Finnish Funding Agency for Technology and Innovation. The financial support received from Andritz Oy, Danisco Sweeteners Oy, Metsa Fibre Oy, Stora Enso Oy and UPM is also gratefully acknowledged. Authors thank Lidia Testova and Karlo Nieminen from Aalto University (Finland) for their help with kinetic modeling.

Share this project:

Related Publications

We use cookies for marketing activities and to offer you a better experience. By clicking “Accept Cookies” you agree with our cookie policy. Read about how we use cookies by clicking "Privacy and Cookie Policy".