On inhibitor reaction pathway with corrosive species and iron surface: Mechanistic and reactive simulation

Abstract

The performance of Z-3,7-dimethylocta-2,6-dien-1-yl isobutyrate (DDI) as a corrosion inhibitor for steel alloys in the presence of different corrosive species was investigated. Different computational approaches were applied to monitor the electronic and geometric properties and conduct molecular dynamic simulations with Gaussian 16 and Forcite. Several parameters were monitored to optimize the interaction with the substrate, in this case, carbon Steel. The chemical calculations by the DFT methods at the B3LYP/6–311++G (d, p) level proved the presence of distinct electronic properties with the highest occupied molecular orbital (HOMO) of 0.34688 eV. These interactions reflect the formation of stable adsorption layers with varying efficiencies. The highest adsorption heat was observed during the interaction with hydrogen ions, which was followed by the chloride and hydroxide ions with 114.186 kcal/mol. Dynamic simulations utilizing the COMPASSIII force field further confirmed the system goes to a stable state and the inhibitor distribution on the iron surface attains a quasi-homogeneous character, which increases the corrosion mitigation potential. These results are indicative of the effectiveness of DDI as a corrosion inhibitor in different industrial applications.