Assessment of inhibitory behavior of ethyl 5-cyano-4-(furan-2-yl)-2-me-thyl-6-oxo-1,4,5,6-tetrahydropyridine-3-carboxylate as a corrosion inhibitor for carbon steel in molar HCl: Theoretical approaches and experimental investigation

The new ethyl 5-cyano-4-(furan-2-yl)-2-methyl-6-oxo-1,4,5,6-tetrahydropyridine-3-carboxylate (THP) has been studied to prevent the electrochemical decomposition of carbon steel in an acidic medium used in the production process using electrochemical techniques (potentiodynamic polarization and electrochemical impedance spectroscopy), weight reduction methods and surface morphological. Computational correlations (DFT and molecular dynamics simulations) were carried out to have more information on the mechanism of inhibition. Experimentally obtained results revealed that the inhibition efficiency increases with the concen-tration, and the highest effectiveness is reached for 10-3M, with 95.22%, and the compound is classified as a mixed inhibitor. Indeed, the increase in temperature caused an increase in the values of icorr throughout the studied temperature range. Moreover, the obtained results showed that the adsorption on carbon steel is accomplished according to the Langmuir adsorption model and the adsorption parameters reflect that the THP is spontaneously adsorbed by physical adsorption, which increases the barrier energy required for the corrosion reaction. The theoretical approaches used show that THP suggests a perfect adsorption by all its chemical structure.

Automated summary

The new compound THP was studied for its inhibitive effect on the electrochemical decomposition of carbon steel in an acidic medium. Experimental and computational results showed that THP exhibited mixed inhibition with the highest effectiveness at a concentration of 10-3M. Adsorption on carbon steel followed the Langmuir model, and the adsorption parameters indicated physical adsorption, increasing the barrier energy for corrosion reaction.