Synthesis and potential applications of aminoantipyrinoanthracenyl imine as corrosion inhibitor of mild steel in H2SO4 medium

Abstract

In the present investigation, a simple and facile method for the synthesis of a novel heterocyclic compound aminoantipyrinoanthracenyl imine (AAPAI) was reported using microwave assisted synthesis and probing their corrosion inhibiting nature towards the corrosion of mild steel (MS) in acidic medium. AAPAI was synthesized through microwave assisted reactions of 4-aminoantipyrine and 9-anthracene and characterized using FT-IR, UV-visible and 1H-NMR spectroscopy. The as-prepared AAPAI was utilized as a corrosion inhibitor of mild steel (MS) in H2SO4 medium. The acid corrosion inhibition effect of AAPAI is analyzed by weight loss measurement, electrochemical characterization like potentiodynamic polarization (PDP) and electrical impedance spectroscopy (EIS) and morphological characterization using a scanning electron microscope (SEM). Weight loss measurements suggested that the inhibition efficiency increases with an increase in AAPAI concentration whereas it slightly decreases with temperature. EIS studies showed the increase in charge-transfer resistance () with AAPAI concentration in the acid solution indicating the ability of AAPAI to prevent the corrosion of MS due to the formation of a preventive film on MS with a maximum efficiency of 86.4% at 1.5 mM concentration. Besides, PDP results demonstrate that the AAPAI molecule behaves like a mixed-type inhibitor. Further, morphological characterization using SEM revealed the protecting ability of AAPAI from corrosion. The adsorption of AAPAI on MS surface follows Langmuir adsorption isotherm and the adsorption of AAPAI on MS involves both chemisorption and physisorption.