Synthesis and corrosion inhibition studies of 1-(4-chlorobenzoyl)thiourea derivatives on mild steel in 1.0 M HCL

Three compounds of benzoylthiourea derivatives namely: 1-(4-chlorobenzoyl)-3-(4-fluorophenyl)thiourea (T1), 1-(4-chlorobenzoyl)-3-(3-chloro-2-fluorophenyl)thiourea (T2), and 1-(4-chlorobenzoyl)-3-(6-chloro-2-fluoro-3- methoxyphenyl)thiourea (T3), were successfully synthesized and characterized via micro elemental analyser, Fourier Transform Infra Red (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy methods. From the FTIR spectral data, the compounds are common to have the vibration frequency of stretching of v(N�H) around 3500�3100 cm?1, v(C=O) around 1660�1720 cm?1, v(C=S) around 680�1440 cm?1 and v(C=N) in the range 1350�1000 cm?1. The inhibition property of the resulted compound on the corrosion of mild steel in 1.0 M hydrochloric acid has been investigated at room temperature using weight loss measurement and linear polarization resistance technique. The inhibition efficiency obtained from both methods are in good agreement with one another. It was found that the inhibition efficiency increases with inhibitor concentration and maximum efficiency was obtained at 0.0004 M. Among the studied inhibitors, T3 shows the best inhibition efficiency of greater than 90%. The potentiodynamic study also reveals that the compounds studied acts essentially as mixed type inhibitor. � 2017 American Scientific Publishers All rights reserved.