Steel-Corrosion Inhibitors Derived from Soybean Oil

Soybean oil derivatives containing a Schiff-base (SOS-B) were prepared and evaluated as microbial corrosion inhibitors against sulfate-reducing bacteria using the gram-positive Desulfosporosinus orientis bacteria as a representative bacterium. These SOS-B compounds were also found to be excellent inhibitors against acidic corrosion of carbon steel. These soybean oil derivatives were prepared by ozonation of soybean oil to yield aldehyde functional intermediates which were then reacted with benzylamine to produce a mixture of imine functional triglycerides and linear compounds. The structure of these soy-based derivatives was confirmed by FTIR and NMR. It was found that the addition of these SOS-B compounds to D. orientis culture provided a complete inhibition of this bacterium. Furthermore, almost no corrosion of carbon steel panels was observed when the panels were aged in 2N HCl solution containing 10 ppm of these SOS-B compounds.