Extraction of Vegetable oil from Acrocomia aculeata Kernels for the Development of Corrosion Inhibitors

This study presents the extraction of vegetable oil from Acrocomia aculeata kernels. That oil was characterized by infrared spectroscopy and gas chromatographic methods. It was found that oil is composed of medium-fatty methyl esters. The aim is to synthesize imidazoline compounds from A. aculeata oil and evaluate their effectiveness as corrosion inhibitors. Static corrosion experiments were carried out to study the effect of the synthesized imidazolines on the CO₂ corrosion of the AISI-1810 carbon steel. The influence of synthesized imidazolines on the corrosion processes was examined by open circuit potential, linear polarization resistance, potentiodynamic polarization, and electrochemical impedance spectroscopy. The results showed that the corrosion rate decreases from 8.31 to 1.0 mm•y^-1 with 100 ppm A. aculeata imidazoline (IM-AA). However, the inhibition efficiency (IE) was below 90%, which was attributed to the composition of the A. aculeata oil. That oil contains predominantly medium-chain fatty acids, and the resulting imidazolines offer limited corrosion protection due to their shorter hydrocarbon chains. Then, IM-AA was mixed with oleic imidazoline (IM-OL) to study the effect of long-chain imidazolines on the inhibition performance. The results showed a significant reduction in the corrosion rate from 8.31 to 0.66 mm•y^-1, achieving an IE greater than 90%. Moreover, the biodegradability of IM-AA and IM-OL ranged between 28 and 36%, indicating that these compounds can be effectively used in combination for the development of corrosion inhibitors. These findings highlight that long-chain imidazolines enhance corrosion inhibition.