The present work evaluated the inhibition properties of (R,S)-2-(dimethylamino)-2-phenylbutyl 3,4,5-trimethoxybenzoate or trimebutine maleate (TM) in aluminum corrosion in 2M hydrochloric acid. Tests were carried out using gravimetric methods and density functional theory (DFT). The results indicate that trimebutine maleate is a good inhibitor of aluminum corrosion in 2M hydrochloric acid at low temperatures. Indeed, the inhibition efficiency of this molecule increases with increasing concentration and decreases with increasing temperature. For an inhibitor concentration of 5.2mM and at 298K, we obtained an inhibition efficiency of 93.61%. The adsorption process is spontaneous, exothermic and follows the Langmuir model. The activation parameters were calculated and analyzed. DFT at the B3LYP/6-311G (d.p) level was used to determine molecular parameters such as EHOMO, ELUMO, ΔE, η, S, μ , A, I, χ, ΔN, ω. These theoretical parameters showed that TM is highly reactive and can both donate and receive electrons from aluminum. They thus confirmed the good inhibition performance of the molecule studied. These parameters were used to explain the inhibition efficiencies obtained. Local selectivity was analyzed using Fukui functions and the dual descriptor to determine possible nucleophilic and electrophilic attack sites.

Trimebutine maleate; corrosion; aluminum; hydrochloric acid; density functional theory; gravimetric methods.