Effect of leucine on the activation energy of the corrosion process of St3 steel in 0,04% CH3COOH solution – kerosene system

Abstract

In this investigation we studied the temperature dependence of the protection effect of St3 steel against corrosion in 0,04% CH3COOH solution-kerosene system by gravimetric method of leucine (derivative of aliphatic monoamino monocarboxylic acids – AL-MAMCA: with the general formula CH3-CH(CH3)-CH2-CH(NH2)-COOH). Previously at 20 ºC we investigated this corrosion process in various two-phase acid and neutral electrolyte solutions in hydrocarbon systems and revealed a good protection effect of leucine. On the basis of the obtained data, the activation energy in the corrosion process of St3 steel has been calculated without and in the presence of the leucine in the aggressive system shown by analytical and graphical methods (graph of dependence of lgK on 1/T). It was found that the addition of leucine to the aggressive system in terms of corrosion causes a significant increase in the activation energy of St3 steel in the corrosion process, and thus complicates the process of this undesirable process. It has been shown that in parallel with the increase in the temperature of the aggressive environment in terms of corrosion, the previously physically adsorbed leucine molecules on the surface of St3 steel are gradually replaced by chemically adsorbed ones, thus further strengthening the metal – inhibitor bond.