SYNTHESIS, CHARACTERIZATION AND THERMAL PROPERTIES OF 2,2′-DIBENZIMIDAZOLYL BUTANE AS A NOVEL CORROSION INHIBITORS FOR MILD STEEL IN SULFURIC ACID

Abstract

This work aims at synthesis and characterization of 2,2[Formula: see text]-dibenzimidazolyl butane as an effective corrosion inhibitor of mild steel in sulfuric acid solution. A simple and efficient method for its synthesis in described. The chemical structure and surface morphology of 2,2[Formula: see text]-dibenzimidazolyl butane were characterized by mass spectrometry (MS), Fourier transform infrared (FTIR), Raman, 1H, [Formula: see text]C NMR spectroscopy and transmission electron microscopy (TEM). Its thermal decomposition and its variation in mass was studied by thermogravimetric analysis (TGA) coupled with differential thermal analysis (DTA). The molecular mass of 2,2[Formula: see text]-dibenzimidazolyl butane was determined to be at 290[Formula: see text]g/mol and its degradation was achieved at 455∘C. Then, the corrosion inhibition efficiency of 2,2[Formula: see text]-dibenzimidazolyl butane was studied with various concentrations in 0.5 M H2SO4 solution for mild steel by the potentiodynamic polarization and the electrochemical measurements. According to the results of electrochemical impedance spectroscopy, the inhibition efficiency decreased with concentration and reached its maximum (95.5%) at 100[Formula: see text]ppm. The polarization measurements showed that the prepared inhibitor acts as a cathodic type inhibitor. The mass loss tests are in accordance with the results of electrochemical measurements.