Delving Ethyl 2-Oxo-2H-Chromene-3-Carboxylate as a Corrosion Inhibitor for Aluminum in Acidic Environments

Abstract

Preserving metals by inhibiting corrosion is crucial; however, many traditional inhibitors are environmentally hazardous due to their toxicity and non-biodegradability. Therefore, this study proposes ethyl 2-oxo-2H-chromene-3-carboxylate as an eco-friendly corrosion inhibitor. The analysis was carried out on aluminum in a hydrochloric acid molar solution using gravimetry and Density Functional Theory (DFT). The findings revealed that ethyl 2-oxo-2H-chromene-3-carboxylate exhibited significant inhibition with an efficiency of 90.5% at a concentration of 5.10-4 M at 45°C. The adsorption behavior followed the Temkin model, indicating favorable surface interactions. Additionally, a lower activation energy in the inhibited medium and endothermic dissolution of aluminum, as indicated by the calculated thermodynamic parameters, suggest chemical adsorption. DFT calculations revealed a negative fraction (ΔN = -0.153 eV), indicating that chemisorption was facilitated by electron transfer from the 3s orbital of aluminum to ethyl 2-oxo-2H-chromene-3-carboxylate. Frontier orbital analysis highlighted active sites at O16, C9, and C13 atoms, supporting the mechanisms of molecular adsorption.