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  • 1
    Electronic Resource
    Electronic Resource
    Structure and reactivity of α,β-unsaturated ethers. VI. Cationic copolymerization of β-chlorovinyl ethyl ether (1969)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 7 (1969), S. 2433-2435 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1969.150070841
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  • 2
    Electronic Resource
    Electronic Resource
    Structure and reactivity of α,β-unsaturated ethers. VII. Electronic effects of the β-methyl substitution on the cationic polymerizabilities of alkyl vinyl ethersPresented in part at the 16th Polymer Symposium in Japan, Fukuoka, October 1967. (1969)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 7 (1969), S. 3219-3228 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactivities of propenyl alkyl ethers toward various cationic agents are summarized, and the effects of a β-methyl group and geometrical isomerism are discussed on the basis of the extended Hückel molecular orbital theory. The reactions considered include cationic polymerization, acid-catalyzed hydrolysis, and silver-ion complexation. The effects of a β-methyl substitution on the reactivity of vinyl ether are different depending on the type of the reactions. The substitution enhances the reactivity of vinyl ether in homogeneous polymerization, whereas it reduces the reactivity in hydrolysis. This contrasting effect of a β-methyl group was found to be compatible with the results of the theoretical calculations of the electronic energy changes accompanying the formation of the relevant transition states. A π-complex-type transition state was concluded for the cationic polymerization. Several lines of experimental evidence in support of the conclusion are presented.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1969.150071116
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  • 3
    Electronic Resource
    Electronic Resource
    Structure and reactivity of α,β-unsaturated ethers. V. Cationic copolymerizations of ring-substituted phenyl vinyl ethers (1969)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 7 (1969), S. 1447-1454 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phenyl vinyl ether (M1) has been copolymerized with its various ring-substituted derivatives (M2) in toluene at -78°C with stannic tetrachloride as catalyst. The substituents investigated include p-CH3O, m-CH3O, p-CH3, m-CH3, p-Cl, and m-Cl. The course of copolymerization was followed by gas chromatographic determinations of residual monomers, and the monomer reactivity ratios were evaluated by use of the integral form of the Mayo-Lewis copolymerization equation. Except for the unusual case of the m-CH3O derivative, the observed values of log (1/r1) were found to be linearly correlated with Hammett's σ constants, the reaction constant being ρ = -1.76 with the correlation coefficient r = 0.990. Comparisons of these results with the existing data for the styrene copolymerizations have enlightened the behavior of the oxygen atom in transmitting the electronic effects of ring substituents onto the reaction center.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1969.150070608
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  • 4
    Electronic Resource
    Electronic Resource
    Structure and reactivity α,β-unsaturated ethers. II. Cationic copolymerizations of propenyl isobutyl etherPresented in part at the IUPAC International Symposium on Macromolecular Chemistry, Tokyo-Kyoto, October 1966. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 6 (1968), S. 993-1000 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: cis- and trans-Propenyl isobutyl ethers were copolymerized with each other and each with vinyl isobutyl ether separately under various conditions. In homogeneous polymerizations a cis-β-methyl substitution on vinyl isobutyl ether apparently enhanced the reactivity, whereas the trans substitution tended to reduce it slightly. In heterogeneous catalysis, on the other hand, a β-methyl group on the vinyl ether, whether cis or trans, greatly reduced the reactivity, probably because of the steric hindrance toward the adsorption of monomers on the catalyst surface. The relative reactivities of cis- and trans-propenyl isobutyl ethers ranged from 2 to 20, depending on the polymerization conditions. The polymer end formed from the cis monomer exhibited special steric effects. It was concluded that even in homogeneous media the rotation of the polymer end around the terminal carbon-carbon bond is restricted.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.150060428
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  • 5
    Electronic Resource
    Electronic Resource
    Structure and reactivity of α,β-unsaturated ethers. III. Cationic copolymerizations of alkenyl alkyl ethers (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 6 (1968), S. 1001-1007 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The relative cationic polymerizabilities of the geometrical isomers of various alkenyl alkyl ethers were studied both in copolymerizations with each other and in their respective copolymerizations with vinyl isobutyl ether as standard. Copolymerizations were carried out in methylene dichloride at -78°C. with boron trifluoride etherate as catalyst. The cis isomers have been found to be more reactive than the corresponding trans isomers. A primary alkyl substituent on the β-cis position of vinyl ethyl ether enhances the reactivity. Yet the steric effect is noticeable when the substituents are bulky. Compounds substituted with cis-β-isobutyl and with β-dimethyl showed little tendency to homopolymerization. It was proved that the polymer ends derived from cis and from trans monomers are respectively different in character because of the restricted rotation of the end unit around the terminal carbon-carbon bond. The alternation tendency, remarkable in the copolymerization of cis monomers with vinyl ether, was explained in terms of the cis-opening mechanism.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.150060429
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  • 6
    Electronic Resource
    Electronic Resource
    Structure and reactivity of α,β-unsaturated ethers. VIII. Cationic copolymerizations and acetal additions of propenyl and isobutenyl ethyl ethers (1969)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 7 (1969), S. 3045-3052 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cationic copolymerizations of cis- and trans-propenyl ethyl ethers (PEE) with isobutenyl ethyl ether (IBEE) were carried out in methylene chloride at -78°C with the use of boron trifluoride etherate as catalyst. Monomer reactivity ratios were r1 = 24.0 ± 2.4 and r2 = 0.02 ± 0.02 for the cis-PEE (M1)-IBEE (M2) system and r1 = 19.1 ± 1.8 and r2 = 0.04 ± 0.02 for the trans-PEE (M1)-IBEE (M2) system, indicative of the reactivity order: cis-PEE 〉 trans-PEE ≫ IBEE. In separate experiments, these β-methyl-substituted vinyl ethers were allowed to react with various acetals in the presence of boron trifluoride etherate. The relative reactivities of these ethers were generally found to decrease in the order: cis-β-monomethylvinyl 〉 vinyl 〉 trans-β-monomethylvinyl 〉 β,β-dimethylvinyl. Comparisons of these results with previously published copolymerization data have permitted the conclusion that, in both the copolymerizations and acetal additions, the single β-methyl substitution on vinyl ethers exerts little steric effect against their additions toward any alkoxycarbonium ion, whereas the β,β-dimethyl substitution results in a large adverse steric effect toward both β-monomethyl- and β,β-dimethyl-substituted alkoxycarbonium ions.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1969.150071101
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  • 7
    Electronic Resource
    Electronic Resource
    Cationic polymerization of 1-ethoxy-1,3-butadiene (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 9 (1971), S. 163-174 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: cis- and trans-1-Ethoxy-1,3-butadienes were polymerized by a variety of cationic agents in various solvents at -78°C. The trans ether, which is the more stable isomer, was found to have greater polymerizability than the cis ether. The trans monomer gave polymers predominantly of the trans-1,4 type, whereas the cis monomer showed a tendency toward the formation of polymers having the microstructure of the 1,2 type. It was concluded that, in the cis ether, the carbon atom which is the most vulnerable to the attack of carbonium ions is the one at the 2-position, whereas, in the case of the trans isomer, the terminal 4-carbon is the most reactive center. The conclusion was confirmed from the results of acetal addition reaction catalyzed by boron trifluoride etherate. The marked contrast in the mode of reaction of the two isomeric ethers toward carbonium ions was interpreted in terms of the difference in the degree of bonding in the transition state.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.150090115
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