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  • 3‐dimethy‐2‐imidazolidinone solvent system  (1)
  • living polymerization  (1)
  • 1
    ISSN: 1572-882X
    Keywords: LiCl/1 ; 3‐dimethy‐2‐imidazolidinone solvent system ; homogeneous cellulose solution ; cellulose acetate ; O‐methylcellulose ; reaction characteristics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In order to elucidate the nature of the LiCl/1,3‐dimethy‐2‐imidazolidinone (DMI) solvent system as one of the homogeneous reaction media of cellulose, cellulose acetate (CA) and O‐methylcellulose (MC) were prepared using this solvent system, and the distribution of substituents within anhydroglucose units was examined by 13C‐NMR. It was found that (i) homogeneous cellulose solutions can be easily prepared by heating 2, 5–12 and 100 parts of weight of cellulose, LiCl, and DMI, respectively, and (ii) the relative reactivity of hydroxyl groups is in the order C‐6 〉 C‐2 〉 C‐3 for both CA and MC. A remarkable feature of this solvent system is that the reaction efficiency in etherification is very high compared with other homogeneous solvent systems.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 751-757 
    ISSN: 0887-624X
    Keywords: controlled synthesis ; glycopolymer ; pendant D-glucosamine residue ; vinyl ether ; living polymerization ; cationic polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: D-glucosamine-containing glycopolymers with well-controlled structure were synthesized by living cationic polymerization. To this end, D-glucosamine-containing vinyl ether (VE) of the type [CH2(=)CH(OCH2CH2OR)] was prepared, where R denotes a 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimide-β-D-glucopyranoside, i.e., the hydroxyl and amino groups in D-glucosamine residues are protected by acetyl and phthaloyl groups, respectively. It was found that (1) the efficient living cationic polymerization of VE monomer is achieved by a combination of ethylaluminum dichloride (EtAlCl2) with an adduct of trifluoroacetic acid (TFA) and isobutyl VE (IBVE) [CH3CH(OiBu)OCOCF3] (i.e., TFA/EtAlCl2 initiating system); and (2) the polymerization in toluene at the elevated temperature (0°C) is most suitable to proceed the homogeneous polymerization over the whole conversion range. The molecular weight distribution of the resulting polymers was very narrow (\documentclass{article}\pagestyle{empty}\begin{document}$ {\bar M}_w/{\bar M}_n \sim 1.1 $\end{document}). Quantitative deprotection of the resulting precursor polymers was successfully achieved with hydrazine monohydrate to afford the corresponding water-soluble polymers with pendant D-glucosamine residues. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 751-757, 1997
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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