Effect of Temperatures on Green Synthesis of Amide-based Corrosion Inhibitors from Sustainable Source

Abstract

This research addresses the critical need for effective anticorrosion solutions, focusing on the development of environmentally friendly coatings using Palm Fatty Acid Distillate (PFAD), a byproduct of crude palm oil production, as a key component in amide inhibitors. Traditional inorganic corrosion inhibitors pose environmental and economic concern due to their expense and toxicity while PFAD based amides promote a sustainable and cost-effective alternative. The synthesis of PFAD based amides using ethylenediamine in ethanol at reflux at various temperatures (25, 40, 60 and 90˚C) revealed that higher synthesis temperatures enhance inhibition properties. Amides containing double bonds and nitrogen-functional groups demonstrated excellent efficiency in attaching to metal surfaces. This study evaluates the synthesized amide’s inhibitory potential through physicochemical analysis using Fourier Transform Infrared Spectroscopy (FTIR) and corrosion inhibition efficiency using the Linear Polarization Resistance Method (LPRM). Physicochemical analysis using FTIR indicated the prominence of the amide group of N-H in the product with clear bonds at 1600 cm⁻¹, and visible amide groups of O-H at 3350 cm⁻¹. They showed the disappearance of the carboxylic acid (C=O) peak from the raw material of PFAD, indicating that the amide synthesis reaction occurred successfully. LPRM analysis revealed that the amides at 90°C achieved a 75% corrosion inhibition efficiency in a 3.5% NaCl solution, outperforming other tested temperatures. This efficiency is attributed to the adsorption of nitrogen-containing fatty amide molecules on the metal surface. These findings highlight the potential of PFAD based amides as green corrosion inhibitors, offering a promising solution for sustainable corrosion mitigation strategies.