Atmospheric corrosion and eco-friendly corrosion inhibitors based on vegetable oils as an effective components of preventive fluids

The problem of atmospheric corrosion is comprehensively described, with the main factors affecting the process such as relative humidity, temperature, and atmospheric pollutants being indicated. It is emphasized that the use of corrosion preventive fluids is the most economically efficient approach for protecting metal equipment in aggressive environments over a certain period of time. Monoethanolamides were synthesized from cottonseed oil at various molar ratios (1:1–1:3) and tested as corrosion inhibitor components in corrosion preventive fluids on carbon steel St10 plates. For this purpose, compositions were prepared by adding 5% and 10% amounts of the monoethanolamides to T-30 turbine oil, and their effectiveness was studied under aggressive conditions, including a Q-4 hydro chamber, seawater, and a 0.001% sulfuric acid solution. The highest protective performance values were determined to be 178 days in the Q-4 hydro chamber, 158 days in seawater, and 157 days in the 0.001% sulfuric acid solution. The structures of the synthesized monoethanolamides were confirmed by IR spectroscopy, and for the compositions exhibiting the highest performance, key physicochemical properties such as density, kinematic viscosity, and freezing point were characterized. The results were compared with those of previous studies conducted using vegetable oils and ethanolamines as raw materials, and general formulas were established for the protective efficiencies of corrosion preventive fluids prepared with such compounds as corrosion inhibitor components. The analysis indicated that ethanolamides synthesized from sunflower oil exhibited higher protection efficiency than those synthesized from cottonseed oil, while diethanolamides were superior to monoethanolamides in terms of protective activity. The sequence of effectiveness according to the molar ratio of the initial materials was 1:1 < 1:2 < 1:3. Compositions exhibiting high performance can be applied as corrosion preventive fluids for protection against atmospheric corrosion encountered in various industrial sectors, including oil and gas, defense, machinery manufacturing, and agriculture, as well as in everyday applications.