ISSN:
1572-882X
Keywords:
regio-selectively substituted cellulose hetero-esters
;
X-ray fibre diagram
;
electron diffraction diagrams
;
conformational analysis
;
packing analysis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Abstract The molecular and crystal structure of cellulose acetate dipropanoate (CADP, 6-O-acetyl-2,3-di O-propanoyl cellulose) has been determined by using a constrained linked-atom least-squares refinement method, combined with X-ray and electron diffractograms and stereochemical refinement. The diffraction analysis indicated that CADP crystallized in a P2 1 monoclinic space group with unit cell parameters:a =1.088 nm,b (unique axis)=1.593 nm,c (fibre axis)=1.509 nm and β =94.1°. The best model derived from combining the stereochemical refinement with the diffraction intensities gave R=0.217 (R″=0.195) for the three-dimensional information from the X-ray fibre diagram and R=0.198 for the base plane data resulting from electron diffraction analysis. In the model, the crystal structure of CADP consisted of a system of right-handed threefold helices packed in an antiparallel fashion, with two molecules passing through the unit cell.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02228794
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