Novel Synthesis of Some N-Hydroxy Phthalimide Derivatives with Investigation of Its Corrosion Inhibition for Carbon Steel in HCl Solution

In the current study, new derivatives were synthesized by reaction of Nhydroxyphthalimide with chloro acetyl chloride in the presence of Et3N as a base to form 1,3-dioxoisoindolin-2-yl 2-chloroacetate (B1), which in turn enters several reactions with different amines where it interacts with primary amines to give 1,3-dioxoisoindolin-2-yl acetate derivatives (B2-B4) in basic medium, in the same way it interacts with these amines but with adding KNCS to form thiourea derivatives (B5-B7). It also reacts with diamines to give bis(azanediyl) derivatives (compounds B8-B10). The prepared derivatives were diagnosed using infrared FTIR and 1HNMR,13CNMR for some derivatives. Compounds B4, B5 and B9 were measured as corrosion inhibitors the inhibition efficiency varied from 85% to 99% and thermodynamic functions, i.e. Gibbs free energy, activation energy, enthalpy, entropy, were calculated for the derivatives at a concentration of (50 ppm) when mixed with carbon steel as additives and exposing the plate to an acidic medium of hydrochloric acid at a concentration of (1M) in different temperatures. The results revealed that as the temperature increases, the inhibition efficiency decreases.