Solution-State One- and Two-Dimensional NMR Spectroscopy of High-Molecular-Weight Cellulose.

Autor: Holding AJ; Laboratory of Organic Chemistry, Department of Chemistry, University of Helsinki, A.I. Virtasen aukio 1 (Chemicum), PL 55, 00014 University of, Helsinki, Finland., Mäkelä V; Laboratory of Organic Chemistry, Department of Chemistry, University of Helsinki, A.I. Virtasen aukio 1 (Chemicum), PL 55, 00014 University of, Helsinki, Finland., Tolonen L; Department of Forest Products Technology, School of Chemical Technology, Aalto University, P.O. Box 11000, 00076, Aalto, Finland., Sixta H; Department of Forest Products Technology, School of Chemical Technology, Aalto University, P.O. Box 11000, 00076, Aalto, Finland., Kilpeläinen I; Laboratory of Organic Chemistry, Department of Chemistry, University of Helsinki, A.I. Virtasen aukio 1 (Chemicum), PL 55, 00014 University of, Helsinki, Finland. ilkka.kilpelainen@helsinki.fi., King AW; Laboratory of Organic Chemistry, Department of Chemistry, University of Helsinki, A.I. Virtasen aukio 1 (Chemicum), PL 55, 00014 University of, Helsinki, Finland. alistair.king@helsinki.fi.
Jazyk: angličtina
Zdroj: ChemSusChem [ChemSusChem] 2016 Apr 21; Vol. 9 (8), pp. 880-92. Date of Electronic Publication: 2016 Mar 24.
DOI: 10.1002/cssc.201501511
Abstrakt: High-molecular-weight celluloses (which even include bacterial cellulose) can be dissolved fully in methyltrioctylphosphonium acetate/[D6 ]DMSO solutions to allow the measurement of resonance-overlap-free 1 D and 2 D NMR spectra. This is achieved by a simple and non-destructive dissolution method, without solvent suppression, pre-treatment or deuteration of the ionic component. We studied a range of cellulose samples by using various NMR experiments to make an a priori assignment of the cellulose resonances. Chain-end resonances are also visible in the (1) H NMR spectrum. This allows the rough determination of the degree of polymerisation (DP) of a sample for low-DP celluloses by the integration of non-reducing chain ends C1 versus polymeric cellobiose C1. Low-DP celluloses show a good agreement with the gel-permeation chromatography (GPC) values, but high-DP pulps show more deviation. For high-purity pulps (pre-hydrolysis kraft and sulfite), residual xyloses and mannoses can also be identified from the (1) H-(13) C heteronuclear single-quantum coherence (HSQC) spectra. Resonances are thus assigned for the common polymeric polysaccharides found in chemical pulps.
(© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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