New Compounds Derived from Nitrophenol Synthesis, Structural Investigation and Anticorrosion Properties

A new azo compound 3 [2-((4-hydroxy-3-(E)-(2-hydroxy-5-nitrophenyl)diazenyl)benzaldehyde] and the azo-Schiff derivative 4 [2-((4-hydroxy-3-((E)-(2-hydroxy-5-nitrophenyl)diazenyl)benzylidene)amino)-4-nitrophenol[ (azo-Schiff 4) have been synthesized. 13C-NMR, 1H-NMR, FT-IR, mass spectroscopy and UV-Vis analysis was used to characterized new compounds. The new synthesized compound azo-Schiff 4 was utilized to inhibit mild steel (MS) corrosion at little concentrations (0.001–0.006 M). Weight loss measurements studies in 1 M HCl and at 298 K showed that azo-Schiff 4 has a good corrosion inhibition efficiency, 75% at 0.002 M of inhibitors. It was found that adsorption methods follow Langmuir isotherm with ΔG values around –23.8 kJ/mol; this confirms that a stable protective film is formed spontaneously during physical adsorption on the mild steel.