The potentiometric titration curves of acids of different types
were studied using piperidine and tetra-n-butylammonium hydroxide,
(Bu4NOH), as titrants in acetonitrile (AN) as solvent. The
effect of methanol addition on the shape of the potentiometric
curves was discussed.
The dissociation constants, KHA, and homoconjugation constants,
KHA2- , of some acids were potentiometrically determined in
AN. No exact correlation was found between KHA of the studied
acids in AN and the corresponding values-in water. It was concluded
that the acid characteristics, its anion properties, and the solvent
. type are the most important factors determining KHA2-.
The heteroconjugation constants, KAHA,- of some anions with
different acids were also determined. K AHAc values for some substituted
benzoic acids with reference to acetate ion were found to
follow a linear free energy relationship with Hammett substituent
constants
