APOLAR INFLUENCES IN POLY[4(5)-VINYLIMIDAZOLE] CATALYZED HYDROLYSES OF 3-NITRO-4-ACYLOXYBENZOIC ACID SUBSTRATES
APOLAR INFLUENCES IN POLY[4(5)-VINYLIMIDAZOLE] CATALYZED HYDROLYSES OF 3-NITRO-4-ACYLOXYBENZOIC ACID SUBSTRATES
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DOI：
10.1021/ja00799a030
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发表时间：
1973-01-01
影响因子：
15
通讯作者：
VANDEWYE.PH
中科院分区：
文献类型：
--
作者：
OVERBERG.CG;GLOWAKY, RC;VANDEWYE.PH
The effects of the acylchain length in the substrate and volume per cent of water in the aqueous-alcohol solvent systems on the rate of hydrolysis of 3-nitro-4-acyloxybenzoic acid substrates (S „-) catalyzed by imidazole (Im) and poly [4 (5)-vinylimidazole](PVIm) were determined. They demonstrate the importance of apolar bonding in therate enhancements observed for PVIm catalyzed reactions as compared to Im catalyzed reactions. The critical micelle concentrations (cmc) of the substrates in aqueous-alcohol solutions were determined spectroscopically. Knowledge of cmc values permitted a more meaningful interpretation of the kinetic data. In certain esterol-ysis reactions, deviations from pseudo-first-order kinetics were observed. With [S7-]>[PVIm] in 15 and 20% 1-propanol-water systems, the kinetic behavior exhibited was indicative of “saturation” of the polymer with substrate. When [PVIm]>[S2-, S7 “, or Svr] cases were studied in 20% 1-propanol in water systems, an analogous saturation of the substrate with polymer was indicated by the kinetic behavior. The effect of varying the pH and temperature on these esterolysisreactions was also studied. An increase in r (r= kpvim/kim) was observed with decreasing pH.
