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  • 1
    Electronic Resource
    Electronic Resource
    The Effect of hydrophobic-lipophilic interactions on chemical reactivity. 12. Mechanistic investigations of NaCMA-catalyzed hydrolysis of esters (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 143-151 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dependence of the catalytic efficiencies of sodium carboxymethylamylose (NaCMA) for the hydrolysis of N-lauryl-3-acetoxypyridinium iodide (1) and p-nitrophenyl dodecanoate (3) on its degree of substitution (D. S. = 0·00, 0·12, 0·18, 0·24, 0·29 and 0·35) and on the pH values of the solutions (pH = 7·32, 7·80, 8·10 and 9·30) have been studied. At fixed D. S. values, the observed hydrolysis rates of 1 and 3 increase with increasing concentrations of NaCMA and follow saturation kinetics. At fixed concentration of NaCMA, the rates increase with decreasing D. S. values until they reach maxima at D. S. = 0·00. Furthermore, at any D. S. value the catalytic efficiency increases with increasing pH values of the solutions. All these results indicate that the hydroxyl groups are actually the principal catalyzing groups.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010304
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  • 2
    Electronic Resource
    Electronic Resource
    The effect of hydrophobic-lipophilic interactions on chemical reactivity. 11. The dependence of the wrapping-up capability of sodium carboxymethylamylose on its degree of substitution (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 133-141 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dependency of the wrapping-up capability of sodium carboxymethylamylose (NaCMA) on its degree of substitution (D. S. = 0·00, 0·12, 0·18, 0·24, 0·29, 0·35 and 0·41) have been studied, using two guest species, iodine and cetyl-trimethylammonium bromide (CTAB). The λmax values of NaCMA-iodine helical inclusion complexes decrease with increasing D. S. values and the amounts of encapsulated iodine by NaCMA as measured by amperometric titrations also decrease with increasing D. S. values. With CTAB as the substrate, the largest number of binding sites, n, and the dissociation constants Kd have been determined by the method of surface tension versus the CTAB concentration plots. The results show that n decreases while Kd increases with increasing D. S. values. All these observations point to the fact that the wrapping-up capability of NaCMA decreases with increasing degrees of substitution. The results are discussed in terms of host-guest and host-solvent hydrophobic-lipophilic interactions as well as intramolecular hydrogen-bonding.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010303
    Location Call Number Limitation Availability
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    Paper (German National Licenses)
    Fulltext
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