A Potentiometric Study of the Acid Dissociation and Cationic Homoconjugation Equlibria in Substituted Pyridine N-Oxide Systems in Binary Polar Solvents, Acetonitrile-Acetone and Acetonitrile-Dimethyl Sulfoxide

• Autorzy: Wróbel R.
• Języki publikacji: EN

Abstrakty

EN

Acid dissociation constants of protonated substituted pyridine N-oxides and cationic homoconjugation constants of these acids with conjugate N-oxides have been determined by potentiometric titration in mixed polar non-aqueous solvents (acetonitrile - acetone and acetonitrile - dimethyl sulfoxide) with increasing (from 0 to 1) mole fraction of acetonitrile. In acetonitrile - dimethyl sulfoxide mixtures, the acid dissociation constants (expressed as pKa) and cationic homoconjugation constants (expressed as log KBHB+) vary non-linearly with increasing mole fraction of acetonitrile. In systems with the least basic N-oxides, local minima of pKa have been observed. In acetonitrile-acetone mixtures, both the pKa and the cationic homoconjugation constant values changed irregularly in the acid-base systems studied and the character of those variations could not be unambiguously determined.

Słowa kluczowe

EN

binary solvents systems; acid-base equilibria; substituted pyridine N-oxides

• Wydawca: Polskie Towarzystwo Chemiczne
• Czasopismo: Polish Journal of Chemistry
• Rocznik: 2001
• Tom: Vol. 75, nr 9
• Strony: 1341--1350

Twórcy

autor

Wróbel R.

• Department of General Chemistry, University of Gdańsk, Sobieskiego 18, 80-952, Gdańsk, Poland