Fatty Amides from Crude Rice Bran Oil as Green Corrosion Inhibitors

Abstract

Due to its high oil content, this research proposes the use of an agroindustrial byproduct (rice bran) as a sustainable option for the synthesis of corrosion inhibitors. From the crude rice bran oil, the synthesis of fatty amide-type corrosion inhibitors was carried out. The corrosion inhibitory capacity of the fatty amides was evaluated on an API X-70 steel using electrochemical techniques such as real-time corrosion monitoring and potentiodynamic polarization curves. As a corrosive medium, a CO2-saturated solution (3.5% NaCl) was used at three temperatures (30, 50, and 70°C) and different concentrations of inhibitor (0, 5, 10, 25, 50, and 100 ppm). The results demonstrate that the sustainable use of agroindustrial byproducts is a good alternative to the synthesis of environmentally friendly inhibitors with high corrosion inhibition efficiencies.

Performance of an amide-based inhibitor derived from coffee bagasse oil as corrosion inhibitor for X70 steel in CO2-saturated brine

“…As a corrosion inhibitor, a fatty acid amide synthesized from coffee bagasse oil was used. The synthesis procedure was according to the procedure reported in the literature (5,8). The details of the synthesis and the characterization of the inhibitor have been reported by the authors in a previous publication (10).…”

“…Various methods have been used to mitigate the problems caused by the CO 2 corrosion process, being the injection of corrosion inhibitors one of the most extensively investigated (4). A corrosion inhibitor can be defined as a compound that, when added in small quantities in an aggressive environment, decreases the corrosion rate without modifying the composition of the corrosive medium (5). The corrosion inhibitors can be classified depending on the source and the way in which they affect the different corrosive processes that are carried out onto metal surface.…”

“…The corrosion inhibitors can be classified depending on the source and the way in which they affect the different corrosive processes that are carried out onto metal surface. Different parameters influence the choice of a corrosion inhibitor, being the main ones, its inhibition efficiency and its impact on the environment (5).…”

“…Most corrosion inhibitors of organic origin have the ability to be adsorbed on the metal surface forming layers of hydrophobic films that limit the mass transport of aggressive species. The adsorption capacity of this type of inhibitors is related to the presence of heteroatoms such as N, O, P and S in the molecular structure (5,7,8).…”

“…Currently, new sources of organic corrosion inhibitors have been investigated due to their low or no toxicity and excellent performance. One of the most studied sources are the vegetable oils with high content of unsaturated fatty acids, this type of oils when reacting with amines-type compounds can form corrosion inhibitors as amines, amides and imidazolines of fatty acids (5,7,8). A particularity of these compounds is that their molecule is formed by the following main components: a polar group (integrated by oxygen, nitrogen, phosphorus or sulfur atoms) which interacts strongly with the metal surface by means of dipolar forces or a coordinated type bond, and a non-polar group (hydrophobic hydrocarbon chain) which acts as a barrier between the metal surface and electrolyte (7,9).…”