An Investigation on N-Containing Organic Compounds as Corrosion Inhibitors for Carbon Steel in Saline Environment

Abstract

The adsorption types of corrosion inhibitors are typically organic compounds made-up of element comprising of N, O, P and S. In this study, the relative inhibition effect of synthesized fatty amides mixture, pyridine and pyrrole as corrosion inhibitors on carbon steels in saline water had been compared using linear polarization resistance method (LPRM). It is still unknown which of these organic compounds performed best than another. The experimental results had shown that compounds containing elemental N performed as corrosion inhibitor in protecting carbon steels when immersed in saline water. The synthesized fatty amides mixture is found to be better than pyridine and pyrrole, indicating the presence of various chain lengths of fatty amides molecules provide a better surface on carbon steels.

Comparative Inhibition Effect of Synthesized Fatty Amides Mixture, Pyridine and Pyrrole on Carbon Steel in Saline Environment

“…Both, pyridine and pyrrole are compounds containing nitrogen atom, π bonds and the aromatic rings in their structure and these are features for major adsorption centers [6]. However, since PFAD (reactant) contains high amount of free fatty acids (81.7%), with carbon atom numbering from 2 to 18 per molecule [9], therefore the product fatty amide inhibitor contained various chain-length of aliphatic amides and help in improving the performance of a single organic amine inhibitor molecule. In addition, the presence of components such as glycerides (14.4%), hydrocarbons (1.47%), tecopherols and tecotienol (0.48%) in PFAD's composition [10] also contributed in giving surface resistances to the inward diffusion of oxygen molecule to the steel surfaces [9].…”