Insights into the borohydride reduction of dialdehyde cellulose: the dilemma of competing reduction and β-elimination reactions

Jonas Simon, Lukas Fliri, Flavia Fröhlich, Janak Sapkota, Matti Ristolainen, Michael Hummel, Thomas Rosenau*, Antje Potthast*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

1 Citation (Scopus)
4 Downloads (Pure)

Abstract

Borohydride reduction of dialdehyde cellulose (DAC) is a promising strategy to generate dialcohol cellulose as bio-based alternative to petroleum-based materials. However, the degradation of the polymer backbone according to β-elimination mechanisms limits the practical applications of the reaction. Therefore, we aimed at optimizing the process to suppress degradation reactions by varying reaction time, pH, and reagent stoichiometry. The degree of oxidation (DO) of the DAC intermediates significantly impacts the yields and molecular weights of the isolated dialcohol celluloses, with a “leveling-off” effect at higher DO values. Increasing the amount of sodium borohydride can minimize—but not entirely prevent—chain scissions. Lowering the pH value during reduction slows down the degradation but results in incomplete conversion of the aldehyde functionalities. Our study provides valuable insights into the consequences of side reactions during borohydride reduction of DAC as well as into chemistry and analysis of the dialdehyde cellulose/dialcohol cellulose system. Graphical abstract: About a dilemma in cellulose chemistry: Dialcohol cellulose derived by periodate oxidation and subsequent borohydride reduction of cellulose has received increasing attention in the development of sustainable thermoplastic materials. The present study highlights the challenge of suppressing β-elimination and favoring the reduction pathway to optimize reaction conditions and minimize chain degradation.

Original languageEnglish
Pages (from-to)8205-8220
Number of pages16
JournalCellulose
Volume30
Issue number13
Early online date7 Jul 2023
DOIs
Publication statusPublished - Sept 2023
MoE publication typeA1 Journal article-refereed

Keywords

  • Cellulose
  • Dialdehyde cellulose
  • Gel permeation chromatography
  • Periodate oxidation
  • Reduction
  • Renewable resources
  • “Level-off” DP

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