Solvents effects on aromatic nucleophilic substitutions. Part 5. Kinetics of the reactions of 1-fluoro-2,4-dinitrobenzene with piperidine in aprotic solvents

The kinetics of the reaction between 1-fluoro-2,4-dinitrobenzene and piperidine were studied in toluene, benzene, dioxane, trichloroethane, tetrahydrofuran, chlorobenzene, ethyl acetate, chloroform, dichloromethane, acetone, acetonitrile, and nitromethane. The second-order rate coefficient is almost...

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Publicado: 1987
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_1472779X_v_n8_p951_Nudelman
http://hdl.handle.net/20.500.12110/paper_1472779X_v_n8_p951_Nudelman
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling paper:paper_1472779X_v_n8_p951_Nudelman2023-06-08T16:17:31Z Solvents effects on aromatic nucleophilic substitutions. Part 5. Kinetics of the reactions of 1-fluoro-2,4-dinitrobenzene with piperidine in aprotic solvents The kinetics of the reaction between 1-fluoro-2,4-dinitrobenzene and piperidine were studied in toluene, benzene, dioxane, trichloroethane, tetrahydrofuran, chlorobenzene, ethyl acetate, chloroform, dichloromethane, acetone, acetonitrile, and nitromethane. The second-order rate coefficient is almost insensitive to the amine concentration in chloroform, acetonitrile, and nitromethane; for the other solvents this value of k3/k2 is greater than 102, indicating neat base catalysis. The trend in k3/k2 does not follow the solvent basicity order; the solvents insensitive to base catalysis are those which exhibit hydrogen-bond donor (HBD) properties. These results are interpreted as an indication that in this reaction the detachment of the nucleofuge is the rate-limiting step in most of the aprotic solvents studied; those solvents which are H B D assist the departure of fluoride, and the formation of the intermediate is the rate-determining step. This conclusion was confirmed by kF/k Cl determinations. A simple linear energy solvation correlation was found between the parameter ET(30) and kA obtained at [B] < 10-2M. For higher amine contents increasing deviations were found. 1987 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_1472779X_v_n8_p951_Nudelman http://hdl.handle.net/20.500.12110/paper_1472779X_v_n8_p951_Nudelman
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description The kinetics of the reaction between 1-fluoro-2,4-dinitrobenzene and piperidine were studied in toluene, benzene, dioxane, trichloroethane, tetrahydrofuran, chlorobenzene, ethyl acetate, chloroform, dichloromethane, acetone, acetonitrile, and nitromethane. The second-order rate coefficient is almost insensitive to the amine concentration in chloroform, acetonitrile, and nitromethane; for the other solvents this value of k3/k2 is greater than 102, indicating neat base catalysis. The trend in k3/k2 does not follow the solvent basicity order; the solvents insensitive to base catalysis are those which exhibit hydrogen-bond donor (HBD) properties. These results are interpreted as an indication that in this reaction the detachment of the nucleofuge is the rate-limiting step in most of the aprotic solvents studied; those solvents which are H B D assist the departure of fluoride, and the formation of the intermediate is the rate-determining step. This conclusion was confirmed by kF/k Cl determinations. A simple linear energy solvation correlation was found between the parameter ET(30) and kA obtained at [B] < 10-2M. For higher amine contents increasing deviations were found.
title Solvents effects on aromatic nucleophilic substitutions. Part 5. Kinetics of the reactions of 1-fluoro-2,4-dinitrobenzene with piperidine in aprotic solvents
spellingShingle Solvents effects on aromatic nucleophilic substitutions. Part 5. Kinetics of the reactions of 1-fluoro-2,4-dinitrobenzene with piperidine in aprotic solvents
title_short Solvents effects on aromatic nucleophilic substitutions. Part 5. Kinetics of the reactions of 1-fluoro-2,4-dinitrobenzene with piperidine in aprotic solvents
title_full Solvents effects on aromatic nucleophilic substitutions. Part 5. Kinetics of the reactions of 1-fluoro-2,4-dinitrobenzene with piperidine in aprotic solvents
title_fullStr Solvents effects on aromatic nucleophilic substitutions. Part 5. Kinetics of the reactions of 1-fluoro-2,4-dinitrobenzene with piperidine in aprotic solvents
title_full_unstemmed Solvents effects on aromatic nucleophilic substitutions. Part 5. Kinetics of the reactions of 1-fluoro-2,4-dinitrobenzene with piperidine in aprotic solvents
title_sort solvents effects on aromatic nucleophilic substitutions. part 5. kinetics of the reactions of 1-fluoro-2,4-dinitrobenzene with piperidine in aprotic solvents
publishDate 1987
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_1472779X_v_n8_p951_Nudelman
http://hdl.handle.net/20.500.12110/paper_1472779X_v_n8_p951_Nudelman
_version_ 1768541909489287168

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