Synthesis and Mechanosynthesis of N, N?-bis (2-thyenilethyl)-2,3-butanodiimine with corrosion inhibitor properties
Abstract
In this work, we report the conventional and mechanochemical synthesis of the ?-diimine
derivate 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 and
elemental analysis. The products were also electrochemically evaluated by potentiodynamic
polarization 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 compound
obtained 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 transfer
of high-charge density which in the delocalization region (N=C?C=N) is formed by p (C=N) and
SH, these moiety play an important role, because their electron lone pairs help to form a protective
coating to form an adsorption layer. The results showed that cysteamine compound turns out to be a
good corrosion inhibitor for the steel iron surface in an acid medium forming an adsorption film
over metallic surface.