Synthesis, Characterization and Corrosion Inhibition Studies of o,m,p-Decanoyl Thiourea Derivatives on Mild Steel in 0.1 M H2SO4 Solutions

A series of decanoyl thiourea derivatives, namely N-decanoyl-N'-2-pyridine thiourea (D1), N-decanoyl-N'-3-pyridine thiourea (D2) and N-decanoyl-N'-4-pyridine thiourea (D3) were successfully synthesized and were applied as corrosion inhibitors. The compounds were characterized via elemental analyser, Fourier Transform Infra Red (FTIR) and 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopies. The inhibition efficiency of each compound was studied on the corrosion of mild steel in 0.1 M H2SO4 with different concentrations of the compounds by using weight loss method and linear polarization resistance technique. From both techniques the results indicate that the corrosion process was significantly reduced with the presence of such compounds. It shows that compound D3 has the highest efficiency which is 85.84 % compared to D1 and D2. The effects of position of N atom located at ortho, meta and para in chemical structure of pyridine on the corrosion inhibition efficiencies of the compounds were also investigated. (author)