ortho Effects on Nucleophilic Aromatic Substitution. The Reactions of 6-R-2-Nitrochlorobenzenes with Piperidine in Benzene
The rate constants and thermodynamic parameters for the reaction of nine 6-R-2-nitrochlorobenzenes with piperidine in benzene have been determined. The reactions follow the Hammett relationship log (kR/kH) = σρ if the "bulky" substituents, bromine and methyl, are excluded. An approximate v...
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| Formato: | JOUR |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00223263_v30_n10_p3365_Sbarbati |
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| Sumario: | The rate constants and thermodynamic parameters for the reaction of nine 6-R-2-nitrochlorobenzenes with piperidine in benzene have been determined. The reactions follow the Hammett relationship log (kR/kH) = σρ if the "bulky" substituents, bromine and methyl, are excluded. An approximate van der Waals radius of 1.9 Å. is proposed as the lower limit below which steric effects are negligible, and differences in rate are mainly determined by polar effects. The substituent influence on both enthalpy and entropy of activation is discussed. © 1965, American Chemical Society. All rights reserved. |
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