Anionic ring -opening polymerization of optically active epoxides.
Item
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Title
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Anionic ring -opening polymerization of optically active epoxides.
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Identifier
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AAI9946234
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identifier
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9946234
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Creator
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Yu, Wei Hong.
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Contributor
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Advisers: Howard Haubenstock | George Odian
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Date
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1999
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Polymer | Chemistry, Organic
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Abstract
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Two new homopolymers, poly(2R,3S)-epoxide and poly(2S,3S)-epoxide have been synthesized via a ring-opening polymerization of (2R,3S)-3,4-epoxy-1,2-O-sopropylidenebutane-1,2-diol and (2S,3S)-3,4-epoxy-1,2-O-isopropylidenebutane-1,2-diol with potassium tert-butoxide or cesium hydroxide as initiators, and characterized by means of IR, 1-D and 2-D 1H and 13C NMR, GC, GPC and optical rotation measurement.*.;The poly(2R,3S)-epoxide only dissolves in very strong protonic solvents while the poly(2S,3S)-epoxide dissolves in some common solvents, such as chloroform, benzene, etc. Specific rotations of the poly(2S,3S)-epoxide have negative values in benzene and positive values in chloroform.;A linear increase in the molecular weights with conversions was observed in bulk polymerization of the (2S,3S)-epoxide with potassium tert -buoxide as initiator at 30°C. Molecular weight distributions of the polymers were relatively narrow. Polymerization mechanism of the (2S,3S)-epoxide prepared with tert-BuOK as initiator was revealed by the end-group analysis of the 13C NMR spectrum.;Copolymerization of the (2R,3S)/(2S,3S)-epoxides and the (2R,3S)/(2S,3R)-epoxides at various ratios have been carried out. The studies showed that when copolymerizations of the (2R,3S)/(2S,3S)-epoxides were carried out starting with a monomer mixture consisting of (2R,3S)/(2S,3S) = 70/30 using tert-BuOK as initiator, (2R,3S)-monomer was incorporated into polymer chain preferentially over (2S,3S)-monomer.;*Please refer to dissertation for diagrams.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
