Novel Biobased Nonionic Surfactants: Synthesis, Surface Activity and Corrosion Inhibition Efficiency Against Aluminum Alloy Dissolution in Acidic Media

Four nonionic surfactants were prepared from the reaction of propylene oxide with oleic acid, linoleic acid, and the free fatty acid mixture from hydrolysis of jatropha oil. The chemical structures of the prepared surfactants were confirmed using IR and NMR spectroscopy. The surface activities of the prepared surfactants were dependent on the polypropylene oxide chain length and also on the nature of the alkyl chains. The nonionic surfactants were evaluated at different concentrations as corrosion inhibitors against the corrosion of Al 6061 aluminum in 2 M HCl solution. The corrosion inhibition tendencies of the surfactants were completely dependent on the fatty acid ratio in the jatropha oil and also on the polypropylene oxide chain length. The corrosion inhibition efficiencies of the surfactants were correlated to their chemical structure and their surface activities.