Triazolic compounds as corrosion inhibitors for copper in hydrochloric acid

Purpose To correlate the inhibitory effect of triazole compounds on the corrosion of copper in HCl at various temperatures by semi‐empirical molecular orbital theory. Design/methodology/approach Two triazoles were selected as the best inhibitors among the triazole compounds tested. Gravimetric and electrochemical measurements were conducted. Findings Correlation between inhibition efficiency and calculation of molecular orbital of triazole compounds was obtained. Cu(I)‐triazole complex formation was confirmed by UV spectroscopy. Research limitations/implications The calculation of energetic levels of molecular orbital may be a tool to explain the classification of inhibitor efficiency. Practical implications The theoretical calculation is a complementary mean to selecting an efficient inhibitor among a given series. Good agreement between the experimental methods explored and theoretical calculations was observed. Originality/value The originality of this work was the finding of the correlation between energetic levels of orbital molecular and inhibitor efficiency of triazole compounds. The confirmation of the formation of Cu(I)‐triazole by UV‐visible spectroscopy was also new.