Synthesis and Mechanosynthesis of N, N?-bis (2-thyenilethyl)-2,3-butanodiimine with corrosion inhibitor properties

In this work, we report the conventional and mechanochemical synthesis of the ?-diiminederivate of 2, 3-butanedione and the primary amine 2-aminoethanethiol designated DD-DC and DDDC/MS respectively. The products were characterized by 1H and 13C-NMR, FT-IR, MS-EI andelemental analysis. The products were also electrochemically evaluated by potentiodynamicpolarization technique in order to measure their corrosion inhibition efficiency on AISI 1018 steel,immersed in a corrosive solution type NACE TM 0177. The results indicate that the compoundobtained under mechanosynthesis conditions, DD-DC/MS, presents better inhibitory properties with 53% efficiency at 10 ppm concentration. On the other hand, the compound obtained by conventional synthesis (DD-DC) presented efficiency of 29% at 10 ppm concentration. Also, the DFT results show that ?-diimine derivatives possesses corrosion inhibition properties, consisting of the transferof high-charge density which in the delocalization region (N=C?C=N) is formed by p (C=N) andSH, these moiety play an important role, because their electron lone pairs help to form a protectivecoating to form an adsorption layer. The results showed that cysteamine compound turns out to be agood corrosion inhibitor for the steel iron surface in an acid medium forming an adsorption filmover metallic surface.