ISSN:
0022-3832
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
The rates of acid-base catalyzed reactions of small molecules in polyelectrolyte solutions should, in general, differ from rates in simple electrolytes at the same pH. The effect is due to the small ionic activity coefficients and the counterion distribution in polyelectrolyte solution and will be accentuated if there is an energetic interaction between the polyion and the reacting molecules. In predicting the reactivity of groups attached to polyions, both electrostatic factors and specific chemical effects have to be considered. The reactivity of p-nitrophenyl ester groups in neutral solution was observed to be increased by a factor of a million when groups were attached to a polymeric acid and the effect was interpreted by a change in the reaction mechanism. The rate of the basic hydrolysis of p-nitroanilide groups attached to polymeric acids was very low and depended strongly on the substitution of both the α and the γ carbon. The pronounced acceleration of the hydrolysis by small concentrations of barium ions was interpreted as a chelation effect. The possible use of polyelectrolytes with reactive side chains as models of enzyme-substrate complexes is discussed.
Zusätzliches Material:
3 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pol.1955.120168217
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