Avaliação da atividade anticorrosiva das formulações com tiossemicarbazonas e extrato das folhas de Talinum triangulare

Abstract

For this dissertation, 4 compounds from the thiosemicarbazone family have been synthesized. Two extracts from the vegetable species Talinum triangulare were prepared in order to evaluate the effectiveness of the formulations xiii containing thiosemicarbazone and the plant extracts as corrosion inhibitors, one in ethyl acetate, and the other in water. All the compounds were obtained at satisfactory purity and good yields. Thiosemicarbazones were characterized by 1H NMR. Previously, analyses of all the compounds and formulations were performed by UV-Vis spectroscopy, which gave information about the molecules capability of forming complex ions with Fe2+. Based on these results, some formulations were selected for the evaluation of their anticorrosive activity. Thiosemicarbazones, T. triangulare extract in ethyl acetate, and their formulations were tested against AISI 1020 carbon steel corrosion in a HCl 1M solution. For this evaluation, gravimetric methods of mass loss and electrochemical techniques of Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy were utilized. Results have shown that the formulations had better percentages of corrosion inhibition than the thiosemicarbazones and the T. triangulare extract in ethyl acetate individually. The various methodologies used for evaluating, UV-Vis spectroscopy, mass loss, Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy, found correlated results; they indicate the formulation containing TIO-3 as the most efficient, showing that the extract in ethyl acetate potentialized the anticorrosive effect.