Medium and structural effects on the ionization constants of some pyrazole carboxylic acid derivatives
| Autor: | Sibel Alkan, Rahmi Kasımoğulları, Alev Doğan, Bülent Zeybek, Yunus Erdoğan, Esma Kılıç |
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| Rok vydání: | 2008 |
| Předmět: |
chemistry.chemical_classification
Ionization constants Chemistry Carboxylic acid Potentiometric titration Inorganic chemistry Ethanol-water mixtures General Chemistry Solvent effect Pyrazole Solvent chemistry.chemical_compound Pyrazole carboxylic acid Ionic strength Ionization Potentiometry Titration Solvent effects |
| Zdroj: | Monatshefte für Chemie - Chemical Monthly. 140:381-386 |
| ISSN: | 1434-4475 0026-9247 |
| DOI: | 10.1007/s00706-008-0037-y |
| Popis: | Stoichiometric ionization constants of some pyrazole carboxylic acids [4-benzoyl-1-(3-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid, 4-benzoyl-1-(4-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid, 4-(ethoxycarbonyl)-1,5-diphenyl-1H-pyrazole-3-carboxylic acid, 4-(ethoxycarbonyl)-1-(3-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid, 4-(ethoxycarbonyl)-1-(4-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid] were determined in ethanol-water mixtures of 50, 60, 70% ethanol (v/v) by a potentiometric titration method. Titrations were performed in an ionic strength of 0.10 M NaCl at 25.0 ± 0.1°C using an Orion 960 automatic titrator under a nitrogen atmosphere. Using the potentiometric titration data, ionization constants were calculated in three different ways. The effects of structure and solvent on the acidity of pyrazole carboxylic acids are also discussed. © 2008 Springer-Verlag. |
| Databáze: | OpenAIRE |
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