Furan and Phenyl Substituted Triazolothiadiazine Derivatives as Copper Corrosion Inhibitors: Electrochemical and DFT Studies

Abstract

This paper presents experimental aspects of two triazolodiathiazine derivatives 1 {1-(6,7-di(furan-2-yl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)ethanol} and 2 {6-phenyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)ethanol} as copper corrosion inhibitors in borate (pH 8.4 and 10.4) aggressive media. Electrochemical findings by CV, polarization and EIS experiments were found inconsistent. The η% values evaluated from all electrochemical methods were in good agreement and within the range of 93–97% at both pH. Compound 1 was found the most efficient corrosion inhibitor for Cu surface at pH 8.4 with inhibition efficiency upto 97%. Electrochemical responses and data interpretation confirmed that the process involved was charge transfer controlled and inhibitors were mixed type. Adsorption data was found best fit in Langmuir’s adsorption isotherm and indicated spontaneity and stability of the compounds on Cu surface via physiosorption. DFT computational studies further supported the experimental results.