The Synthesis and Characterization of Salicylidene L- Asparagine as Corrosion Inhibitor towards Carbon Steel in 1 M

• Main Author: Anisya, Nadia
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/38122
• Institution: Institut Teknologi Bandung

Salicylidene L-asparagine is a Schiff base compound that can be used as a green corrosion inhibitor. Salicylidene L-asparagine has been successfully synthesized through condensation reaction between L-asparagine and salicylaldehyde in basic solution of methanol utilizing MAOS (Microwave-Assisted Organic Synthesis) method at 100 W of irradiation power and temperature of 58 °C for 90 minutes with 76% of chemical yields. The characterizations of synthesized product were performed based on TLC tests using n-hexane and n-hexane: ethyl acetate (9:1) (v/v) as eluents, as well as the measurements of melting point, FTIR and 1H-NMR (48 MHz in metanol) spectroscopy. Salicylidene L-asparagine as the synthesized product has melting point of 140-142 °C. The FTIR spectrum of product showed characteristic peak of C=N stretching vibration at wavenumbers of 1660.9 cm-1, and the 1H-NMR spectrum of product also showed that salicylidene L-asparagine have been successfully synthesized. The measurements of corrosion inhibition activity of salicylidene L-asparagine toward carbon steel in 1 M HCl have been performed utilizing EIS (Electrochemical Impedance Spectroscopy) method at 25 – 45 °C with concentrations of 25 – 250 ppm, as well as Tafel extrapolation method and corrosion wheel test at 35 °C with concentration of 225 ppm. The results of corrosión inhibition activity tests showed that salicylidene L-asparagine has corrosión inhibition efficiency up to 47%. Adsorption process of salicylidene L-asparagine on carbon steel surface follows the Langmuir adsorption isotherm model with Gibbs energy of adsorption, ?Gads of -31.52 kJ/mol. It can be concluded that salicylidene L-asparagine inhibit the corrosion on carbón steel by lowering the rate reaction in anode through the chemiphysiosorption of salicylidene L-asparagine on carbon steel surface.