Study of Synthesis and Corrosion Inhibition of Novel Mannich and Schiff Bases on Carbon Steel in Acid Solution

In this paper, a Schiff base (SB-1) and derivatives (SB-2 and SB-3) was synthesized and characterized by IR and H-1 NMR methods, the corrosion efficiency and mechanism of carbon steel in 1: 1 hydrochloric acid was obtained by weight loss measurements, atomic absorption spectrophotometry, electrochemical measurements, atomic force microscopy studies and quantum chemical calculations. The results indicated that the inhibition efficiency was SB-3 > SB-2 > SB-1 at low concentration of inhibitors. Under high concentration, they have same efficiency. The electrochemical measurements showed that the synthesized compounds is an efficient mix-type inhibitors and its efficiency increased with the increase in inhibitor concentrations. The quantum chemical parameters were calculated using the density functional theory (DFT), and results showed that the inhibitor and the metal surface interacted with the donor-acceptor to achieve the effect of corrosion inhibition.