Linear resistance model of the inhibition mechanism of steel in HCl by triazole and oxadiazole derivatives:: structure-activity correlations

A quantum chemical study of the corrosion inhibition efficiency of triazole and oxadiazole derivatives, at the mild steel electrode, in molar hydrochloric acid (1 M HCl) was carried out. The correlation between the molecular structure and inhibition efficiency of these heterocyclic compounds was investigated using a linear model encompassing the charge transfer resistance (R,). The linear resistance model was optimised with the semi-empirical quantitative structureactivity relationships approach. Regression equations, with multiple correlation coefficients superior at 0.90, were derived between 1/R-t and molecular descriptors. These significant correlations indicated that the variation of the corrosion inhibition with the structure of the inhibitors may be explained in terms of electronic properties. (C) 2002 Elsevier Science Ltd. All rights reserved.