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Cellulose

, Volume 14, Issue 5, pp 457–468 | Cite as

Degradation processes in the cellulose/N-methylmorpholine-N-oxide system studied by HPLC and ESR. Radical formation/recombination kinetics under UV photolysis at 77 K

  • Alexander Konkin
  • Frank Wendler
  • Frank Meister
  • Hans-Klaus Roth
  • Albert Aganov
  • Oliver Ambacher
Article

Abstract

Degradation processes of N-methylmorpholine-N-oxide monohydrate (NMMO), cellulose and cellulose/NMMO solutions were studied by high performance liquid chromatography (HPLC) and electron spin resonance (ESR) spectroscopy. Kinetics of radical accumulation processes under UV (λ = 248 nm) excimer laser flash photolysis was investigated by ESR at 77 K. Beside radical products of cellulose generated and stabilized at low temperature, radicals in NMMO and cellulose/NMMO solutions were studied for the first time in those systems and attributed to nitroxide type radicals ∼CH2–NO–CH2∼ and/or ∼CH2–NO–CH3∼ at the first and methyl CH3 and formyl CHO radicals at the second step of the photo-induced reaction. Kinetic study of radicals revealed that formation and recombination rates of radical reaction depend on cellulose concentration in cellulose/NMMO solutions and additional ingredients, e.g., Fe(II) and propyl gallate. HPLC measurements showed that the concentrations of ring degradation products, e.g., aminoethanol and acetaldehyde, are determined by the composition of the cellulose/NMMO solution. Results based on HPLC are mainly maintained by ESR that supports the assumption concerning a radical initiated ring-opening of NMMO.

Keywords

Cellulose ESR Flash photolysis High performance liquid chromatography (HPLC) N-methylmorpholine-N-oxide Radicals 

Notes

Acknowledgment

The authors wish to express their gratitude to one of the anonymous reviewers whose remarks greatly help to improve the article. Financial support by the German Federal Ministry for Education and Research (BMBF) under contract No. 94/02 is gratefully acknowledged.

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Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  • Alexander Konkin
    • 1
  • Frank Wendler
    • 2
  • Frank Meister
    • 2
  • Hans-Klaus Roth
    • 2
  • Albert Aganov
    • 3
  • Oliver Ambacher
    • 1
  1. 1.Center for Micro and NanotechnologiesTechnical University of IlmenauIlmenauGermany
  2. 2.Centre of Excellence for Polysaccharide ResearchThuringian Institute for Textile and Plastics ResearchRudolstadt-SchwarzaGermany
  3. 3.Physical departmentKazan State UniversityKazanRussia

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