One-shot TEMPO-periodate oxidation of native cellulose

David Joram Mendoza; Christine Browne; Vikram Singh Raghuwanshi; George P Simon; Gil Garnier

doi:10.1016/j.carbpol.2019.115292

One-shot TEMPO-periodate oxidation of native cellulose

Carbohydr Polym. 2019 Dec 15:226:115292. doi: 10.1016/j.carbpol.2019.115292. Epub 2019 Sep 4.

Authors

David Joram Mendoza¹, Christine Browne¹, Vikram Singh Raghuwanshi¹, George P Simon², Gil Garnier³

Affiliations

¹ Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia.
² Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia.
³ Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia. Electronic address: Gil.Garnier@monash.edu.

PMID: 31582089
DOI: 10.1016/j.carbpol.2019.115292

Abstract

TEMPO/NaClO/NaBr and sodium periodate were combined in a one-shot reaction to oxidise cellulose from bleached pulp. Oxidation of cellulose forms two fractions: a highly-carboxylated water-insoluble (up to 1.9 mmol COO^-/g, DS = 0.39) and a water-soluble fraction (up to 4 mmol COO^-/g, DS = 1.1). Results show that these regioselective oxidants work in synergy to produce fully-oxidised 2,3,6-tricarboxycellulose. Increasing the periodate concentration results in fibrillation and extensive depolymerisation of the pulp cellulose as more residual aldehyde groups participate in the depolymerisation process. X-ray diffraction (XRD) reveals that the addition of periodate increases cellulose crystallinity, retains crystal size but slightly alters the XRD pattern. The degree of substitution (DS), which governs the solubility of carboxylated cellulose, can be controlled by varying the periodate concentration. Combining TEMPO/NaBr/NaClO with sodium periodate simultaneously in a one-shot reaction produces low-cost cellulose with controlled level of carboxylation and unique properties.

Keywords: Carboxylated cellulose; Degree of polymerisation (DP); Degree of substitution (DS); Periodate; Solubility; TEMPO.