Comparison of values for phenolic and naphtholice Schiff bases derived from 2-acetyl pyridine (Part ΙΙ)*

Abstract

The study includes the preparation of four phenolic Schiff bases derived from the
2-acetyl pyridine as a mother compound with primary amines o , m , p-amino
phenols and 4-amino naphthol . The structures of these phenolic and naphtholic Schiff
bases were confirmed by physical method , namely UV visible and IR spectroscopy
and melting points.
The main aims of the study was the determination of pKa values for these
hydroxy Schiff bases by potentrometric titration method. This method as found simple
, precise and accurate . pKa estimated , depend on the following factors :-
1. The chemical structure of imine .
2. The ambient temperature .
3. The influence of phenolic group , whether its donating or withdrawing
behavior .
4. The resonance numbers of phenoxide ion in Schiff base .
* See part Ι in reference (16) .