Derivado de oxazinoquinoxalina e sistemas coloidais à base de óleo de coco aplicados como inibidores de corrosão em aço AISI 1018 em meio salino

Abstract

Corrosion is a major problem affecting the industrial sector and carbon steel is the material most industrial applications, especially for the oil processing. The largest sources of oil are located in seas and oceans, and the metal corrosion occurs by the saline environment action. Some quinoxaline derivatives are reported in the literature as being effective agents in inhibiting corrosion. In the present study we evaluated the inhibitory capacity of a derivative oxazinoquinoxalina, N- (2-hydroxyethyl) -2,3-dihydro [1,4] -oxazinequinoxaline (OAQX), aiming carbon steel corrosion protection AISI 1018, in saline (3.5% NaCl). Studies of Resistance Polarization Linear (RPL) showed inhibition efficiencies ranging from 55% to 89% in low concentrations (6 pmm to 100.0 ppm) evaluated samples (OAQX) solubilized in DMSO. For determination of adsorption parameters, Langmuir isotherms were obtained, Temkin and Frumkin. The derivative quinoxaline the oxazinoquinoxalina consisted of the first compound of this class, reported as a corrosion inhibitor, which differs from other organic heterocyclic compounds applied as anticorrosion due to its solubilization in neutral aqueous media which promotes the study of its interactions with the metal-ligand. Due to the worsening of global environmental degradation, new practices have been adopted to control environmental impacts that consist of the development of clean technologies. In this perspective, colloidal systems based on coconut oil (OC) were evaluated as corrosion inhibitors in carbon steel AISI 1018, in saline medium (NaCl). Nanoemulsified OCsystems, were evaluated by Linear Polarization Resistance (LPR) method, affording maximum efficiencies 84% for SNE-OC6 and 90% for SNEOC6-OAQX. Extensively, the colloidal micro- and nanoemulsified OC-systems (SME-OC1, SME-OC2, SNEOC1, SNE-OC1 e SNE-OC6), were effective as carrier of some herbal extracts with proven anticorrosive property, resulting in new corrosion inhibition products for sustainable technological development.