Corrosion Inhibition Potential of Dithiohydrazodicarbonamide Derivatives for Mild Steel in Acid Media: Synthesis, Experimental, DFT, and Monte Carlo Studies

Abstract

In the present work, new compounds, namely 2-fluoro phenyl-2,5-dithiohydrazodicarbonamide (2FPDC) and 4-fluoro phenyl-2,5-dithiohydrazodicarbonamide (4FPDC), were successfully synthesized and examined as corrosion inhibitors for mild steel in 1 M HCl. The molecular structures were characterized by Fourier transform infrared spectroscopy (FT-IR) and 1 H, 13 C nuclear magnetic resonance (NMR). A scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), and atomic force microscope (AFM) were conducted to identify the surface morphology of mild steel in the absence and existence of a corrosion inhibitor. Several electrochemical techniques have been conducted to evaluate inhibitor efficiency. The influence of immersion time on the efficiency of inhibitors was also investigated. The electrochemical results showed that both compounds appeared to be mixed type. However, 4FPDC is slightly more efficient than 2FPDC (97.3% compared with 96.5% at 1 × 10 −2 M and an immersion time of 5 h). The resistance polarization for inhibitors was found to obey an order of 4FPDC > 2FPDC. The Langmuir isotherm system revealed the best match, and the type of adsorption was physisorption and chemisorption in both compounds. SEM and EDX results have confirmed the presence of particles of inhibitor on the metal surface. A smooth surface was observed in the presence of inhibitors approved by AFM. Quantum chemical results showed that the adsorption of molecules of inhibitor takes place predominantly through protonated structures, and strongly agreed with experimental results. The results reveal that excellent inhibition efficiency was attained even in aggressive conditions, and they can be viewed as novel corrosion inhibitors for mild steel with excellent protection. Keywords Materials and Experimental Methods MaterialsA mild steel rod was purchased from a local market with a chemical composition as follows: (Wt.%): 0.18 C,

Effect of flame retardants and 1% stabiliser on thermal decomposition and physics properties of thermoplastic polymer due to TGA and DTA tests

“…Both of these two tests give a more precise outcome by using the Scanning electron microscopic (SEM) images [10], moreover, UL-49 burning and flammability test [12], also for applied TGA and DTA test in this work, and the furnace test [8,9]. Fig.…”

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“…At this temperature, polymer samples will be burn in UL-94, to observe the melt/drip behavior studies of the polymers, also to compare all these processing temperature results with polymers samples with different FR. and additives results, therefore in previous work, the effect of the additives/fillers on various physical and melt dripping behaviors intensity of polymers was explored, in [10,12,13,15].…”

Synthesis, Characterization and Theoretical Anti-Corrosion Study for Substitute Thiazole Contained Cyclobutane Ring

“…Thiazole ring is an electron-rich system that easily forms hydrogen bonds between molecules of different species. Thiazole-containing compounds have been reported to be broad-spectrum inhibitors [34,35]. For this purpose, two novel compounds (IIIa, b) from the thiazole series containing cyclobutane derivatives with thiourea were synthesized.…”

Theoretical inhibitor Calculation for Synthesis of Two New thiazole Derivatives

“…A thiazole ring is an electron-rich system that can easily form hydrogen bonds between molecules with materials in different species. Compounds containing thiazole have been reported to be an inhibitor of broad-spectrum [34,35]. For this purpose, two new compounds (IIIa,b) of the thiazole series containing cyclobutane derivatives with thiourea which are not found in the literature were synthesized.…”