Abstract:
Inhibition of the corrosion of mild steel in 0.1 M H2SO4 by (2S,5S,6R)-6-(2-(aminomethyl)-5-(3-(2-chlorophenyl)isoxazol-5-yl)benzamido)-3,3-dimethyl-7-oxo-4-thia-1 azabicyclo[3.2.0]heptane-2-carboxylic acid (AMPX) was studied using experimental (gravimetric, gasometric and thermometric methods) and quantum chemical methods. The results obtained from the experiments revealed that the %inhibition efficiencies at various concentrations of AMPX decrease with increase in temperature but increased with increasing concentrations. The adsorption of the inhibitor on mild steel surface is spontaneous and supported the Langmuir adsorption model. Synergistic studies between the inhibitor and potassium halides (KI, KBr and KCl) indicated that the inhibition potentials of AMPX can be enhanced through synergistic combinations with halides. Quantum chemical consideration indicated that semi empirical parameters calculated for AMPX are comparable to those of other inhibitors. Results obtained from condensed Fukui function and Huckel charge analyses indicated that the site for electrophilic attack in AMPX is in the amide nitrogen (N14). The energy of interaction and proton affinity for all possible adsorption sites in AMPX have been calculated and from the results obtained, AMPX can easily be protonated, its adsorption is downhill exothermic and preferentially favours the amide nitrogen (N14).
