ISSN:
0323-7648
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
A novel synthetic route to and a polymerization procedure for oxo-crown ethers 2, 11-dioxo-18-crown-6 (1), 2-oxo-12-crown-4 (2) and 2-oxo-21-crown-7 (3) are described. Cyclization of the ω-hydroxycarboxylic acid precursors of 1 - 3 has been achieved by heating these precursors in the presence of a Lewis acid catalyst (CoCl2) and a template salt (MCl). Cyclization yields up to 82% were reached, using CsCl as template salt. Oxo-crown ethers 1 - 3 have been polymerized using SnOct2 as catalyst, giving polymers with molecular weights of approximately 5 kg/mol and dispersities of ca. 1.8 (measured with polyethylene oxide standards). The polymerization of 2 was monitored with 1H-NMR and SEC giving information about (a) the influence of monomer/catalyst ratio and temperature on polymerization rate and (b) the influence of temperature on molecular weight (distribution). The possibility of introducing endgroups into poly(2-oxo-12-crown-4) using SnOct2-catalyzed polymerization was also studied.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/actp.1996.010471103
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