A reduced unit cell derived from the presently accepted unit cell and a new parallel chain arrangement is proposed for cellulose I1 (regenerated cellulose). In the present structure, all the cellulose chains are identical and there is only one chain passing through each unit cell. The intensity data
Structure of a cellulose II-hydrazine complex
β Scribed by David M. Lee; John Blackwell; M. H. Litt
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1983
- Tongue
- English
- Weight
- 929 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0006-3525
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β¦ Synopsis
Synopsis
The structure of a crystalline cellulose 11-hydrazine complex has been determined by x-ray diffraction methods as part of an investigation of cellulose-solvent interaction. The complex studied was that formed when Fortisan fibers were swollen in hydrazine and then vacuumdried. The unit cell is monoclinic with dimensions a = 9.37 .&, b = 19.88 .&, c = 10.39 A, and y = 120.0" and contains disaccharide segments of four chains, with one hydrazine per glucose residue. In view of the limited x-ray intensity data, the structure has been determined based on an approximate unit cell containing two chain segments, with a = 4.69 A, using the linked-atom least-squares refinement procedures. The refined model contains antiparallel cellulose chains that are linked by both intermolecular hydrogen bonds and hydrogen-bonded hydrazine molecules. The parallel chains in the 020 planes are packed in register, leading to stacks of chains analogous to those in chitin. All the hydroxyl groups are satisfactorily hydrogen-bonded, and each hydrazine forms four donor and two acceptor hydrogen bonds, including an N-H-. -N bond between hydrazines. From this work it can be seen that the interaction of cellulose I1 with hydrazine involves scission of the intermolecular hydrogen bonds followed by disruption of the stacks of quarter-staggered chains. The latter effect is probably necessary for hydrazine to act as a cellulose solvent.
π SIMILAR VOLUMES
## Abstract A hydrate of cellulose II can be formed by swelling Fortisan fibers in hydrazine and then washing in water. The hydrate is stable at 93% relative humidity and has a monoclinic unit cell with dimensions __a__ = 9.02 Γ , __b__ = 9.63 Γ , __c__ = 10.34 Γ , and Ξ³ = 116.0Β°; the space group is _
Supermolecular structure of linters cellulose at the cellulose 1-11 phase transition is investigated by wide-angle X-ray scattering (quantitative phase analysis, degree of crystallinity by the method of Ruland and Vonk, and lateral crystallite sizes via peak separation by Pearson VII functions). A s