Synthesis and study of poly[(hydrazinylazo)]thiazoles as potent corrosion inhibitors for cast iron-carbon alloy in molar HCl: A collective computational and experiential methods

Herein, two poly[(hydrazinylazo)]thiazoles derivatives named, Poly[2-(2-(4-methylthiazol-2-yl)hydrazinyl)-4-methyl-5-((4-((4-(diazenyl)phenyl)sulfonyl)phenyl)diazenyl)thiazole] (TZP-1) and Poly[2-(2-(4-methylthiazol-2-yl)hydrazinyl)-4-methyl-5-((3-(diazenyl)phenyl)diazenyl)thiazole] (TZP-2) were regulated good yields by treatment of N-(4-((4-(2-(1-chloro-2-oxo propylidene)-hydrazinyl)phenyl)-sulfonyl)-phenyl)-2-oxopropane hydrazonoyl chloride or 1,3-phenylene bis-(2-oxopropane hydrazonoyl chloride) with hydrazine-1,2-bis-(carbothioamide). The configurations of the polymers are categorized by FT-IR and ¹H NMR spectra. The effect of two synthesized poly[(hydrazinylazo)]thiazoles derivatives on the corrosion protection of cast iron-carbon alloy in acid chloride solution was examined using AC impedance spectroscopy, and potentiodynamic polarization (PPD) methods. The polarization resistance increased, and the corrosion current density declined with increasing polymer dose. TZP-2 revealed the maximum protection capacity P_PDP/%= 97.8% at 50 mg/L. PPD studies exhibited that the performance of the titled polymer as mixed-type inhibitors and competitive chemically and physically adsorbed on alloy interface following the adsorption model of Langmuir. The morphological change of alloy surface was categorized by scanning electron microscopy (SEM). The adsorption energies of investigated poly[(hydrazinylazo)]thiazoles on iron(1 1 0) interfaces were computed by Monte Carlo (MC) simulations. The relation among specific quantum parameters and the protection capacity has been interpreted and recognizable correlations were detected.