A Quantum-chemical Study of the Corrosion Inhibition of Iron by Means of Aniline Derivatives in Hydrochloric Acid

Abstract

When various properties of organic compounds are to be expressed, it is necessary to explore the connection between their experiment and theory. To determine the mechanism of the inhibition process by organic materials, the electron structure of a set of organic compounds is studied and correlated with their electrochemical corrosion measurements. This paper discusses the inhibition of corrosion in 5% hydrochloric acid by means of p-substituted anilines with respect to quantum chemistry.

Characterization of iron surface modified by 2-mercaptobenzothiazole self-assembled monolayers

“…Both of them were larger than that of BT (À647.9 kJ mol À1 ). According to Vosta's theory [31,32], The higher the HOMO energy of the inhibitor, the stronger the bond between the inhibitor and the metal, so we think both of the two forms have stronger interaction with iron than BT. These results may also draw the above conclusion that the exocyclic sulphur atom has great importance in forming the SAMs on iron.…”

“…According to Fukui's frontier orbital approximation [30], interactions occur only between the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) of both reactants. The higher the HOMO energy of the inhibitor, the greater the ease of offering electrons to the unoccupied d orbits of iron, and the stronger the bond between the inhibitor and the metal [31,32], the higher the protection efficiency of the inhibitor. Furthermore, the more negative of the APT atomic charges of MBT molecule, the more chance of the metal accepts the electron to its lowest unoccupied orbits.…”

Anti‐tarnish treatment of brass for coinage (II) color analysis, adsorption model, and quantum chemical calculations

“…According to Fukui's frontier orbital approximation [22], interactions occur only between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of both reactants. The higher the HOMO energy of the inhibitor, the greater the ease of offering electrons to the unoccupied orbits of brass, and the stronger the bond between the inhibitor and the metal [23,24], the higher the protection efficiency of the inhibitor. E LUMO indicates the ability of the molecules to accept electrons.…”

Inhibition of copper corrosion in aerated hydrochloric acid solution by heterocyclic compounds containing a mercapto group

“…Some studies on the inhibitors from the quantum chemistry have been reported [20,21]. Many semi-empirical calculation methods for determining various quantum chemistry properties of organic corrosion inhibitors have been proposed: HMO [22], CNDO [23], MNDO [24], and PPP [25]. The HMO method is the simplest method in quantum chemistry; only p-electrons are considered in this method.…”