Synthesis and evaluation of a novel pyridinyl thiazolidine derivative as an antioxidant and corrosion inhibitor for mild steel in acidic environments

Abstract

A new synthesized (Z)-2-((3,5-dichloropyridin-2-yl)imino)thiazolidin-4-one (DICPT) was evaluated as an antioxidant and a corrosion inhibitor for mild steel (M.STL) in a 0.5 M HCl solution. The antioxidant activity of newly synthesized DICPT was screened using a DPPH assay, and the results showed that DICPT has good antioxidant activity. Electrochemical assessments were conducted utilizing potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). A new compound, DICPT, was synthesized, and its chemical structure was established and validated through various spectroscopic techniques, including including infrared (FTIR), nuclear magnetic resonance (NMR), and mass spectroscopy. PDP measurements revealed DICPT to be a mixed-type inhibitor. Charge transfer resistance (Rct) increased when inhibitor concentrations increased, according to EIS tests. The inhibition efficiency (%I) showed a corresponding rise with increasing inhibitor concentration, peaking at approximately 94.2 % at 3 × 10−5 M. Langmuir’s adsorption isotherm was found to govern the preferred adsorption mode of DICPT molecules onto the metal surface. UV–visible spectra confirmed the chemical interaction between DICPT molecules and the M.STL surface. AFM investigation indicated the formation of a protective layer on the metal surface, shielding it from corrosive environmental factors. Quantum chemical calculations were compared to experimental results to learn more about how corrosion is stopped and how well it works. Our study demonstrates the innovation of DICPT as a dual-function compound, offering both antioxidant and corrosion protection properties. This research contributes to the development of effective corrosion inhibitors for industrial applications.