Synthesis of hydroxylated fatty amide from underutilized seed oil of Khaya senegalensis: a potential green inhibitor of corrosion in aluminum

Background: Corrosion is a serious problem all over the world. Most currently used approach to control corrosion have short comings which necessitates the search for novel materials that are green, cheap, from renewable source, and eco-friendly that can be used to combat this problem of corrosion control. Method: Khaya senegalensis fatty hydroxylamide (KSFA) was synthesized from K. senegalensis seed oil via simple reaction route involving esterification, transesterification, hydroxylation, and amidation reaction. KSFA was characterized using Fourier-transform infrared (FTIR), nuclear magnetic resonance ((HNMR)-H-1), CHN elemental analyzer, particle size distribution (PSD), X-ray diffractometer, zeta potential, thermogravimetric analysis (TG), thermogravimetric-mass spectrometer (TG-MS), and scanning electron micrograph (SEM) coupled with energy dispersion spectroscopy (EDS). Inhibitory effect of KSFA on corrosion of aluminum (Al) in 0.5 M HCl was studied at different concentrations of KSFA and temperatures using weight loss method. Result: Result from gas chromatography (GC) revealed oil of K. senegalensis to predominantly contain C18:1 (68.46%) fatty acid. Hydroxyl and amide functional groups present in KSFA were confirmed by FTIR and (HNMR)-H-1. TG analysis revealed loss in mass around 80-190, 200-450, and above 450 degrees C while TG-MS revealed five different masses with m/z values 16, 17, 18, 28, and 44. Corrosion inhibition capacity of KSFA was by surface adsorption, which is spontaneous, and physisorption and described by Langmuir isotherm. The corrosion inhibition efficiency of KSFA increased with increase in its concentration while its corrosion rate reduced with increase in concentration. Conclusion: The inhibition efficiency of 90.43% exhibited by KSFA and the fact that KSFA was synthesized via non-hazardous process from a renewable sourced biomass is an indication that KSFA is a potential green and efficient inhibitor of corrosion in aluminum. KSFA is simple to use as an inhibitor and easy to prepare.