The constants of ion-pair formation with 3-nitroaniline (3NO2A) for eight halogenoacetic acids (HAAs, 3a-h: TFA, TCA, TBA, DFA, DCA, DBA, MCA, and MBA), and five 2,2-dichloroalkanoic acids containing 3-8 carbon atoms (HAs, 5a-e: DCPA, DCBA, DCMBA, DCVA, and DCOA) have been determined in TOL at 298.1 K. The results obtained brought to evidence for HAAs the formation of ion-pairs with two different stoichiometries (base-acid, 1:1 or 1:2), while in contrast the HAs furnish only the 1:1 pairs. The different steric and electronic requirements of HAAs and HAs seem to be responsible for such an unlikely behavior. At the same time, the acid-catalyzed MRH of the (Z)-phenylhydrazone of 5-amino-3-benzoyl-1,2,4-oxadiazole (1) into (2,5-diphenyl-2H-1,2,3-triazol-4-yl)urea (2) in the presence of the five HAs above has been investigated in TOL at 313.1 K. Thus, in contrast with previous results in the presence of several HAAs, a unique pathway for the rearrangement has been observed, again pointing out the importance of the above effects on the initial acid/base interactions. Finally the acidic strength of TFA against seven nitroanilines (NA, 4a-g: 4NO2A, 3NO2A, 3Me4NO2A, 4Me3NO2A, 2Me3NO2A, 2NO2A, and 3,5diNO2A) characterized by a very different basicity has been measured in TOL at 298.1 K.

D'Anna, F., Frenna, V., Ghelfi, F., Macaluso, G., Marullo, S., Spinelli, D. (2010). Apolar versus polar solvents: a comparison of the strength of some organic acids against different bases in toluene and in water. JOURNAL OF PHYSICAL CHEMISTRY. A, MOLECULES, SPECTROSCOPY, KINETICS, ENVIRONMENT, & GENERAL THEORY, 114, 10969-10974 [10.1021/jp107058x].

Apolar versus polar solvents: a comparison of the strength of some organic acids against different bases in toluene and in water

D'ANNA, Francesca;FRENNA, Vincenzo;MACALUSO, Gabriella;MARULLO, Salvatore;
2010-01-01

Abstract

The constants of ion-pair formation with 3-nitroaniline (3NO2A) for eight halogenoacetic acids (HAAs, 3a-h: TFA, TCA, TBA, DFA, DCA, DBA, MCA, and MBA), and five 2,2-dichloroalkanoic acids containing 3-8 carbon atoms (HAs, 5a-e: DCPA, DCBA, DCMBA, DCVA, and DCOA) have been determined in TOL at 298.1 K. The results obtained brought to evidence for HAAs the formation of ion-pairs with two different stoichiometries (base-acid, 1:1 or 1:2), while in contrast the HAs furnish only the 1:1 pairs. The different steric and electronic requirements of HAAs and HAs seem to be responsible for such an unlikely behavior. At the same time, the acid-catalyzed MRH of the (Z)-phenylhydrazone of 5-amino-3-benzoyl-1,2,4-oxadiazole (1) into (2,5-diphenyl-2H-1,2,3-triazol-4-yl)urea (2) in the presence of the five HAs above has been investigated in TOL at 313.1 K. Thus, in contrast with previous results in the presence of several HAAs, a unique pathway for the rearrangement has been observed, again pointing out the importance of the above effects on the initial acid/base interactions. Finally the acidic strength of TFA against seven nitroanilines (NA, 4a-g: 4NO2A, 3NO2A, 3Me4NO2A, 4Me3NO2A, 2Me3NO2A, 2NO2A, and 3,5diNO2A) characterized by a very different basicity has been measured in TOL at 298.1 K.
2010
Settore CHIM/06 - Chimica Organica
D'Anna, F., Frenna, V., Ghelfi, F., Macaluso, G., Marullo, S., Spinelli, D. (2010). Apolar versus polar solvents: a comparison of the strength of some organic acids against different bases in toluene and in water. JOURNAL OF PHYSICAL CHEMISTRY. A, MOLECULES, SPECTROSCOPY, KINETICS, ENVIRONMENT, & GENERAL THEORY, 114, 10969-10974 [10.1021/jp107058x].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/51231
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