Potentiometric study for Determination of PKa values for Schiff bases derived from 2- acetyl pyridine with heterocyclic amines

Abstract

The project was started by synthesis of two Schiff bases from 2- acetyl pyridine with 4-
amino pyrimidine and 4- amino pyridine by a standard method . The structures of these Schiff
bases had confirmed by physical method , namely by using U.V-IR spectra and melting points .
The main aims of the study was the determination of two consecutive nitrilium ions
ionization constants pK1 and pK2 for in each molecule simultaneously . The last was regarded
an improvement in potentiometric method for determination of pKa in these molecules . Finaly
factors govern , the pK1 or pK2 values in these Schiff base ,as structure of imines, temperature
and mixed solvent of ethanol in the range (10_60) % in water were given and discussed.