Abstract:Corrosion is generally present in metal materials, especially when they are involved in several industrial activities. Their deterioration is induced by the physicochemical interaction between the metal and the corrosive environment, which causes great problems in several activities. The petrol sector is one of the most damaged as the constituents of perforation fluids and petroleum production water influence corrosion. Conventional anti-corrosion techniques are employed to prevent the loss of highly used industrial material; they include coatings, change of environment, cathodic and anodic protection and inhibitor treatments using organic compounds. Broadly speaking, this article describes the main anti-corrosion protection methods, corrosion in petroleum industry, and the anti-corrosion agents used in the industrial sector.Keywords: Corrosion; corrosion inhibitors; anti-corrosion protection; corrosion in petroleum industry. ResumoA corrosão está presente nos materiais metálicos em geral e, em especial, envolvidos nas diversas atividades industriais. A deterioração destes é causada pela interação físico-química entre o material e o meio corrosivo, onde causa grandes problemas nas mais variadas atividades. Um dos setores que mais se prejudica com a corrosão é o petrolífero devido a influencia de constituintes dos fluidos de perfuração e da água de produção. Para evitar as perdas dos materiais de elevado uso industrial, são utilizadas técnicas anticorrosivas que incluem os revestimentos, as técnicas de modificação do meio, a proteção catódica e anódica e, os inibidores de corrosão como a utilização de compostos orgânicos. Este artigo descreve, em linhas gerais, as principais técnicas de proteção anticorrosiva, a corrosão na indústria do petróleo e os agentes anticorrosivos utilizadas no meio industrial.Palavras-chave: Corrosão; inibidores de corrosão; proteção anticorrosiva; corrosão na indústria de petróleo.

Mycotoxigenic fungi can compromise the quality of food, exposing human and animal health at risk. The antifungal activity of eight thiosemicarbazones (1-8) and nine semicarbazones (9-17) was evaluated against Aspergillus flavus, A. nomius, A. ochraceus, A. parasiticus and Fusarium verticillioides. Thiosemicarbazones had MIC values of 125-500 µg/ml. The thiosemicarbazones 1 and 2 exerted fungistatic activity against Aspergillus spp., and thiosemicarbazone 2 exerted fungicidal activity against F. verticillioides. Compound 2 showed an iron chelating effect of 63%. The ergosterol content of A. parasiticus had a decrease of 28 and 71% for the 31.2 and 62.5 µg/ml concentrations of thiosemicarbazone 2 compared to the control. The obtained results of antifungal activity revealed that thiosemicarbazone class was more active when compared to semicarbazone class and, the thiosemicarbazone 2 was the most active compound, specially, against Aspergillus spp.

Thiosemicarbazones belong to a widely pharmacologically and technologically used class of compounds. The heteroatoms (N and S) and double bond in their structure enable them to act as inhibitory agents -an alternative to corrosion control. This work synthesised 2-hydroxybenzaldehydethiosemicarbazone (THIO-6) aiming at its anticorrosive activity against AISI 1020 carbon steel in acid medium; the electrochemical methods Potentiodynamic Polarization and Impedance Electrochemical Spectroscopy were used to investigate it. Results showed great anticorrosive efficiency (94%), even at low concentration (40.10 -5 mol L -1 ). This effect was confirmed by the determination of the doublelayer capacitance (C dl ), which provided information about the protective film formed on the metal surface. The adsorption process obeyed the Langmuir adsorption isotherm and the K ads value from the investigation of THIO-6 adsorption mechanisms on metal surfaces indicated that corrosion inhibition occurred through chemisorption, which identifies it as an effective corrosion inhibitor agent.

Corrosion is a process arising out of a chemical action of the environment on a particular material, causing its deterioration. It may occur in metals, concrete, organic polymers, and others. A promising alternative to prevent corrosion is the use of organic inhibitors. The search for new agents or formulations that enable the diminishing of corrosion effects is evidently necessary; therefore, this work evaluated 3 new formulations which contained thiosemicarbazones 4-hydroxy,3-methoxybenzaldehydethiosemicarbazone, 4-ethoxybenzaldehyde-thiosemicarbazone and 4-hydroxybenzaldehydethiosemicarbazone with the crude extract of Talinum triangulare leaves in ethyl acetate, aiming at the Fe 2+ ion chelation for an anticorrosive action. UV-Vis spectroscopy was used to evaluate the formation of Fe 2+ ion complexes; also, to determine the respective coordination numbers with the thiosemicarbazones. Results indicated the increase of the thiosemicarbazone anticorrosive action, which had been evaluated by molecular modeling and potentiodynamic polarization, when there were crude extract of T. triangulare leaves in the formulation.