Comparison of pKa‾ values for some amino Schiff bases , derived from 3-acetyl and 4-acetyl pyridines by potentiometric method

Abstract

The study included the preparation of six imine compounds , derived from the
mother ketones , namely 3-acetyl and 4-acetyl pyridines by standard method .
The structures of these imines were confirmed by physical methods, namely UV,
IR spectra , beside melting points and qualitative diazotization chemical tests.
The main object of the study was the determination of pKa‾ for conjugate
acids of these imines ,by potentiometric titration with standard HCl solution . The
last was found simple , precise and accurate . The study showed that pKa‾ values for
any imine , depends on the following factors as :-
1- The chemical structures of imines .
2- The temperature under study .
3- The type of intra or inter molecular hydrogen bonding exist in these