Tautomerism study for some macro bi imines derived from benzoin and acetyl acetone

Abstract

Four new macro bi imines as derived from benzoin and acetyl acetone with succinyl
dihydrazide (1) , phthaloyl dihydrazide (2) and 4-amino salicylic acid (3) or 5-amino salicylic
acid (4) were prepared respectively by a standard method. The structures of these bi imines
were confirmed by the measurements of their melting points , UVand IR spectra. The study
deals with the tautomerism reactions for the synthesised compounds in ethanol and by the aid
of UV spectroscopy. The thermodynamics of tautomerism reaction of these bi imines ,
showed that the tautomerism processes as evident from ΔG parameters were spontaneous and
non spontaneous in compound (1,3,4 ) and (2) respectively. The enthalpies of tautomerism
reactions ΔH were varied from exothermic to endothermic reactions and for the same
previous compounds numbers . The entropies of reactions ΔS were also estimated and
discussed. Finally, all thermodynamic parameters evaluated , support the tautomerism
processes in these macro bi imines.