2-(2,4-Dimethoxybenzylidene)-N-Phenylhydrazinecarbothioamide as an Efficient Corrosion Inhibitor for Mild Steel in Acidic Environment

In this work, a new Schiff base, namely 2-(2,4-dimethoxybenzylidene)-N-phenylhydrazinecarbothioamide (DP), was synthesized and fully characterized by some spectroscopical techniques (Fourier Transform Infrared (FT-IR), and Nuclear Magnetic Resonance (1H-NMR and 13C-NMR) in addition to micro elemental analysis-CHN. The newly synthesized corrosion inhibitor was evaluated for its corrosion inhibition performance on mild steel coupons in 1 M hydrochloric acid solution by using gravimetric techniques. The experimental findings of weight loss measurements revealed that the inhibition efficiency increased with the DP concentration and reached a maximum value of 94.8% at the 0.005 M concentration but decreased with reducing temperature (at temperatures ranging from 303 to 333 K). Moreover, the significant inhibition efficiency and the value of ΔGo indicated that DP participates in Chemisorption and Physisorption on the mild steel surface. The adsorption process of the synthesized inhibitor on a mild steel surface follows Langmuir adsorption isotherm. The uninhibited and inhibited surface morphology of the mild steel coupons was investigated using scanning electron microscopy (SEM).