کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
217536 | 1426337 | 2006 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Potentiometric studies of acid-base interactions in substituted 4-nitropyridine N-oxide systems
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
مهندسی شیمی (عمومی)
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چکیده انگلیسی
(Acid + base) equilibrium constants, involving the acidity (pKaAC) and cationic homoconjugation constants (in the form of lgKBHB+AC), have been determined by the potentiometric method in 13 systems formed by substituted 4-nitropyridine N-oxides in the polar aprotic solvent, acetone (AC). The derivatives covered a wide range of proton-acceptor properties and inherent diversified tendencies towards formation of hydrogen-bonded homocomplexed cations. In addition, the constant values (expressed as pKaANandlgKBHB+AN) for two of the systems studied, N-oxides of 2-methylamino- and 2-ethylamino-4-nitropyridine, were determined in acetonitrile (AN). The acidity constants in the non-aqueous media studied have been found to change in line with their substituent effects and the sequence of acidity changes in water. The values of the cationic homoconjugation constants increased with increasing basicity of the N-oxides and decreased with increasing solvent basicity.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The Journal of Chemical Thermodynamics - Volume 38, Issue 5, May 2006, Pages 554-558
Journal: The Journal of Chemical Thermodynamics - Volume 38, Issue 5, May 2006, Pages 554-558
نویسندگان
Åukasz GurzyÅski, Aniela Puszko, Agnieszka Ostrzechowska, Mariusz Makowski, Lech Chmurzyñski,