Abstract

A comparative study for the determination of pKa values of some new imines derived from N Ã?Â?Ã?Â?Ã?Â?Ã?Â? formyl Ã?Â?Ã?Â?Ã?Â?Ã?Â? pipyridine and other imines by potentiometric method

Author(s): A.S.P.Azzouz, H.J.S.Al-Mula

The project is concerned with the synthesis of a new five imines in a forms of syn or anti oxime and phenolic Schiff bases. They are derived from the mother compound the N-formyl pipyridine. Their structures are confirmed by the available physicalmeans, namelyUV, IR spectra andmelting points. The pKa for these five imineswith other eleven imines prepared fromour earlierwork using other 2– furfuryl aldehyde, 4- fluorobenzaldhyde, 4- hydroxylbenzaldhyde and benzil are evaluated by potentiometric method and compared together. The acid strengths of these sixteen acids at 293Kare experimentally governed by two factors. First is the electro negativity of nitrogen atomof pipyridine ring, second the electron donation property of lone pair of electrons available on hetero nitrogen atomof ringmentioned.