The Oxidative Polycondensation of Benzylidene-4′-hydroxyanilene using Air O2, NaOCl and H2O2: Synthesis and Characterization

Abstract

In this work, the oxidative polycondensation reaction conditions of benzylidene-4′-hydroxyanilene (B-4′-HA) were studied using oxidants such as air O2, H2O2 and NaOCl in an aqueous alkaline medium between 40 and 95 ○C. Oligo-benzylidene-4′-hydroxyanilene was characterized by 1H-NMR, FT-IR, UV-Vis, size exclusion chromatography (SEC) and elemental analysis techniques. The solubility of oligomer using organic solvents such as DMF, THF, DMSO, methanol, ethanol, CHCl3, CCl4, toluene, acetonitrile, ethyl acetate was investigated. According to air O2 oxidant (flow rate 8.5 L/h), the conversion of B-4′-HA was 82.0% in optimum conditions such as [B-4′-HA]0=[KOH]0=0.1015 mol/L at 50 ○C for 25 h. According to the SEC analysis, the number-average molecular weight (Mn), weight-average molecular weight (Mw) and polydispersity index (PDI) values of O-B-4′-HA were found to be 1852 g mol−1, 3101 g mol−1 and 1.675; 2123 g mol−1, 4073 g mol−1 and 1.919; 2155 g mol−1, 4164 g mol−1 and 1.932, using air oxygen, NaOCl and H2O2 oxidants, respectively. Also, Thermo gravimetric analysis (TGA) showed oligo-benzylidene-4′-hydroxyanilene to be unstable against thermo-oxidative decomposition. The weight loss of O-B-4′-HA was found to be 95.87% at 1000 ○C.