Synthesis, Characterization and Optimum Reaction Conditions of Oligo-N-Salicylidenephenylhydrazone via Oxidative Polymerization

Abstract

The oxidative polycondensation conditions and optimum parameters of Nsalicylidenephenylhydrazone(SPH) were determined using air, H2O2 and NaOCl as oxidants at atemperature range between 50 °C and 95 °C in an aqueous alkaline medium. The molecularstructures of the obtained monomer and oligomer were confirmed by FT-IR, UV-Vis, 1H-NMR andelemental analyses. The molecular weight distributions of oligo-N-salicylidenephenylhydrazone weredetermined (OSPH) by SEC measurement. Thermal behavior (TG-DTA) of OSPH was examined usingthermogravimetric techniques. The conversion of N-salicylidenephenylhydrazone into its oligomericform was performed using air, H2O2 and NaOCl as oxidants in an aqueous alkaline medium. Accordingto SEC analysis, the number-average molecular weight (Mn), weight-average molecular weight (Mw)and polydispersity index (PDI) values of OSPH obtained using NaOCl oxidant were found to be 1436g mol-1, 1631 g mol-1 and 1.14, respectively. The conversion yield of N-salicylidenephenylhydrazoneinto oligo-N-salicylidenephenylhydrazone was 100% at optimum reaction conditions such as [SPH]0= [KOH]0 = [H2O2]0 =0.06 mol/L and at 90 °C for 10 h. Also, according to TG-DTA analysis, oligo-Nsalicylidenephenylhydrazonewas shown to be thermally stable and resistant to thermo-oxidativedecomposition. The weight loss of OSPH was found to be 20, 50 and 92.56% at 275°, 597° and 1000°C, respectively.