T. Gunduz et al., PROTONATION CONSTANTS OF SOME SUBSTITUTED SALICYLIDENEANILINES IN DIOXAN-WATER MIXTURES, Analytica chimica acta, 282(3), 1993, pp. 489-495
Sixteen Schiff's bases have been prepared from salicylaldehyde and sub
stituted anilines and their stoichiometric protonation constants have
been determined in dioxan-water mixtures of 30, 40, 50 and 60% dioxan
(v/v) using a combined pH electrode at 25 degrees C, under nitrogen at
mosphere. The calculation of the constants has been carried out using
a PKAS computer programme. The effects of the substituents on the prot
onation constants and the additivities of these effects are discussed.
Furthermore, it was found that the log K-OH value increases but the l
og K-NH value decreases for all Schiff's bases if the percentage of di
oxan is increased.