Ionization of Cellobiose in Aqueous Alkali and the Mechanism of Cellulose Dissolution

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

Cellulose, one of the most abundant renewable resources, is insoluble in most common solvents but dissolves in aqueous alkali under a narrow range of conditions. To elucidate the solubilization mechanism, we performed electrophoretic NMR on cellobiose, a subunit of cellulose, showing that cellobiose acts as an acid with two dissociation steps at pH 12 and 13.5. Chemical shift differences between cellobiose in NaOH and NaCl were estimated using 2D NMR and compared to DFT shift differences upon deprotonation. The dissociation steps are the deprotonation of the hemiacetal OH group and the deprotonation of one of four OH groups on the nonreducing anhydroglucose unit. MD simulations reveal that aggregation is suppressed upon charging cellulose chains in solution. Our findings strongly suggest that cellulose is to a large extent charged in concentrated aqueous alkali, a seemingly crucial factor for solubilization. This insight, overlooked in the current literature, is important for understanding cellulose dissolution and for synthesis of new sustainable materials.

Detaljer

Författare
Enheter & grupper
Externa organisationer
  • KTH Royal Institute of Technology
  • SP Technical Research Institute of Sweden
  • Göteborgs universitet
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Fysikalisk kemi
Originalspråkengelska
Sidor (från-till)5044-5048
Antal sidor5
TidskriftThe Journal of Physical Chemistry Letters
Volym7
Utgåva nummer24
StatusPublished - 2016 dec 15
PublikationskategoriForskning
Peer review utfördJa