Selective C6 Oxidation of Cellulose with Oxone in Water
2016 (English)Conference paper, Presentation (Refereed)
A novel method for selective C6 primary alcohol oxidation of cellulose, as an alternative to TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl), was developed. Cellulose pulp and Cladophora nanocellulose were selectively oxidized in a one-pot procedure by Oxone (2KHSO5·KHSO4·K2SO4) and efficient reaction conditions were investigated. The effects of the reactions on the morphology, viscosity and chemical structure of the products obtained were studied. The C6 primary alcohol groups were selectively oxidized to carboxyl groups, as testified by solid-state CP/MAS 13C NMR and FTIR, and the content of carboxyl groups was determined by conductometric titration. SEM, capillary-type viscometry and XRD were applied to characterize the products and to investigate the influence of the oxidation. For the first time, low-cost and stable Oxone was used as a single oxidant to oxidize cellulose into C6-carboxyl cellulose. The oxidation is an inexpensive and convenient process to produce carboxylic groups on the surface of the cellulose fibers and to make the cellulose fibers charged. Particularly, this method can avoid the use of halogens and toxic radicals and constitute a green route to access C6-carboxyl cellulose. Further, sodium bromide could be used as a co-oxidant to Oxone and increase carboxylic acid content by 10% to 20%. The Oxone oxidation is a promising alternative to the frequently employed TEMPO-mediated oxidation of cellulose, which might increase the possibility to develop and improve applications of cellulose.
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IdentifiersURN: urn:nbn:se:uu:diva-310140OAI: oai:DiVA.org:uu-310140DiVA: diva2:1055118
2nd EPNOE Junior Scientists Meeting Sophia-Antipolis (France) – 13&14 October 2016