Micellar effects on the hydrolysis and aminolysis of 2,4-dinitrophenyl sulphate
- 1 January 1972
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 2
- No. 14,p. 2097-2104
- https://doi.org/10.1039/p29720002097
Abstract
Effects of micellar hexadecyltrimethylammonium bromide (CTAB), sodium dodecyl sulphate (NaLS), polyoxyethylene(20) nonylphenol (lgepal CO-850), 3-(dimethyldodecylammonio)-propane-1-sulphonate (DDAPS) and that of their co-micellar mixtures have been investigated on the nucleophilic reactivity of primary, secondary, and tertiary amines toward 2,4-dinitrophenyl sulphate. Observed second-order rate constants, k2,obs have been separated into those due to hydrolysis, K2,hyd, and to nucleophilic attack, K2,nuc. Micellar CTAB, DDAPS, and lgepal CO-850 enhance k2,hyd for the different amines from 4 to 33 fold, while micellar NaLS has no appreciable effect. A more dramatic result is the complete suppression of K2,nuc by micellar CTAB, DDAPS, and mixtures of CTAB and lgepal CO-850 for reactions of hydrazine and morpholine. Sensitivities of hydrolysis to amine basicity (Brønsted β-values) are greater in micellar CTAB, DDAPS, and lgepal CO-850 than in pure water.Keywords
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