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Gravimetric Measurements and Theoretical Calculations of 4-Aminoantipyrine Derivatives as Corrosion Inhibitors for Mild Steel in Hydrochloric Acid Solution: Comparative Studies
Firas F. Sayyid, Ali M. Mustafa, Slafa I. Ibrahim, Mustafa K. Mohsin, Mahdi M. Hanoon, Mohammed H. H. Al-Kaabi, A. A. H. Kadhum, Wan Nor Roslam Wan Isahak, A. A. Al-Amiery
Received: June 28, 2022; Revised: July 02, 2022; Accepted: July 03, 2022
Abstract: Due to continuous promotion of green alternatives to toxic petrochemicals by government policies, research efforts towards the development of green corrosion inhibitors have intensified recently. The objective of the current work was to develop novel green and sustainable corrosion inhibitors derived from 4- aminoantipyrine to effectively prevent corrosion of mild steel in corrosive environments. Gravimetric methods were used to investigate corrosion inhibition of 4-((furan-2-ylmethylene)amino)antipyrine (FAP) and 4-((pyridin-2-ylmethylene)amino)antipyrine (PAP) for mild steel in 1 M HCl. FAP and PAP were subjected to quantum chemical calculations using density functional theory (DFT). DFT was used to determine the mechanism of mild steel corrosion inhibition using inhibitors tested in HCl. Results demonstrated that these tested inhibitors could effectively inhibit mild steel corrosion in 1.0 M HCl. At 0.0005 M, these inhibitors’ efficiencies for FAP and PAP were 93.3% and 96.5%, respectively. The Langmuir adsorption isotherm was obeyed by these inhibitors on the mild steel surface. Values of adsorption free energies, ΔGoads , revealed that FAP followed chemical and physical adsorptions.