Solvent-free synthesis of imidazoline from TETA-palmitic acid and evaluation of its corrosion inhibition activity

Corrosion of steel is a common phenomenon, especially when the steel is in contact with a corrosive medium. The use of corrosion inhibitors such as imidazoline-based compounds is very important to reduce losses due to corrosion. Synthesis and characterization of palmitate-derived imidazoline have been previously studied in a mini laboratory scale using the microwave-assisted organic synthesis (MAOS) method. However, larger scale synthesis of this imidazoline compound and study of its corrosion inhibition has yet to be reported. This research aims to study the scale-up of imidazoline synthesis based on palmitic acid and triethylenetetramine (TETA) which is then used as a corrosion inhibitor for fuel oil pipelines made of carbon steel. The results of the study showed that the optimum conditions for the 27-gram scale reaction were obtained at a reaction temperature of 150°C and a stirring speed of 1000 rpm with a palmitic acid conversion of 93%. Corrosion inhibition test of carbon steel in CO2-saturated 1.5% NaCl solution showed that the use of 500 ppm imidazoline solution provided a corrosion inhibition efficiency of 81%.