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  • 1
    Digitale Medien
    Digitale Medien
    Phase-transfer reactions catalyzed by phosphonium salts bound to macroporous polystyrene supports (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1243-1250 
    Details
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The rate of reaction of alkyl halides with aqueous sodium acetate or cyanide catalyzed by phosphonium salts supported on insoluble polystyrene resins, and rates of ion-exchange of the chloride ion in the catalysts against the acetate ion, were studied as a function of catalyst particle size, the percentage of ring substitution, the morphology of polymer support, and distance between active site and polymer backbone. Rates of 1-bromooctane or benzyl chloride with macroporous, 7-25% ring-substituted catalysts increased with increasing ring substitution. Rates with macroporous catalysts increased as a heptamethylene spacer was introduced between the active site and the polymer backbone. Rates of ion-exchange with macroporous catalysts were facilitated with increasing ring substitution or by the introduction of the spacer chain. A relation between the catalytic activity of macroporous or microporous catalysts and ion-exchange rates under triphase conditions was discussed.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pol.1984.170220604
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  • 2
    Digitale Medien
    Digitale Medien
    Phase-transfer reactions catalyzed by phosphonium salts attached to polystyrene resins by spacer chains (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 3421-3429 
    Details
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The rate of reaction of 1-halooctanes with aqueous sodium cyanide catalyzed by phosphonium salts attached to insoluble polystyrene resins by tetramethylene or heptamethylene spacers was studied as a function of catalyst particle size, degree of polymer crosslinking, percentage of ring substitution, and temperature. Rates of reaction of 1-bromooctane with 17-38% ring-substituted catalysts increased as spacer-chain length increased. Rates of reaction of 1-bromooctane decreased, whether the percentage of ring substitution increased or decreased from 17-19%. Rates of reaction of 1-chlorooctane increased with increasing spacer-chain length and decreasing percentage of ring substitution. Apparent activation energy for the reaction of 1-bromooctane with 9% ring-substituted, spacer-modified catalysts was 9-10 kcal/mol and 13 kcal/mol with 17-19% ring-substituted catalysts. The hydrophilicity of catalysts decreased with increasing spacer-chain length and decreasing percentage of ring substitution. The mechanisms of reaction were discussed in terms of intrinsic reactivity and intraparticle diffusion limitations on the reaction rates.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pol.1982.170201214
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  • 3
    Digitale Medien
    Digitale Medien
    Novel synthesis of spacer-modified polymer supports and activity of phase-transfer catalysts derived from the polymer supports (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 3015-3019 
    Details
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pol.1982.170201028
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  • 4
    Digitale Medien
    Digitale Medien
    Phase-transfer reactions catalyzed by polymer-supported crown ethers (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 911-926 
    Details
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Polymer-supported crown ethers were prepared from chloromethylated or ω-bromoalkylated polystyrene resins and hydroxymethylbenzo-18-crown-6 and 15- or 18-membered monoazacrown ethers. Effects of the cavity size of crown ethers, the degree of crosslinking, the degree of ring substitution, particle size, spacer chains, and solvents on the activity of the polymer-supported crown ethers in the reaction of 1-chloro- or 1-bromo-octane with aqueous NaI or KI were investigated and mechanisms of the reaction were discussed in terms of mass transfer, intraparticle diffusion, and intrinsic reactivity.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pol.1984.170220403
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Solvent effects in phase-transfer reactions prompted by polymer-supported phosphonium salts (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 23 (1985), S. 49-61 
    Details
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Solvent effects on the intrinsic activity of, the ion-exchange rate of, and the overall activity of polymer-supported phosphonium salts under tri-phase conditions were studied. The intrinsic activity of the catalysts as well as of soluble phosphonium salts was dependent only slightly on organic solvents. The exchange rate of the chloride ion in the catalysts against the acetate ion dependent on the solvents when the degree of ring substitution was ≤ 16%. With the ca. 30% ring-substituted catalysts the rate increased and hardly depended on the solvents. The overall reactivity of the catalysts for the reaction of organic halides with NaCN was a function of substrate structure and organic solvents. For alkyl halides such as bromooctane the catalysts were more reactive in good solvents such as toluene or chlorobenzene than in poor solvents such as octane. For arylalkyl halides such as benzyl chloride the catalysts exhibited the opposite effect. In poor solvents the arylalkyl halides are absorbed preferentially into the catalysts.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pol.1985.170230106
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