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 N-hydroxyphthalimide with chloro acetyl chloride in the presence of Et۳N as a base to form ۱,۳-dioxoisoindolin-۲-yl ۲-chloroacetate (B۱), which in turn enters several reactions with different amines where it interacts with primary amines to give ۱,۳-dioxoisoindolin-۲-yl acetate derivatives (B۲-B۴) in basic medium, in the same way it interacts with these amines but with adding KNCS to form thiourea derivatives (B۵-B۷). It also reacts with diamines to give bis(azanediyl) derivatives (compounds B۸-B۱۰). The prepared derivatives were diagnosed using infrared FTIR and ۱HNMR,۱۳CNMR for some derivatives. Compounds B۴, B۵ and B۹ were measured as corrosion inhibitors the inhibition efficiency varied from ۸۵% to ۹۹% and thermodynamic functions, i.e. Gibbs free energy, activation energy, enthalpy, entropy, were calculated for the derivatives at a concentration of (۵۰ ppm) when mixed with carbon steel as additives and exposing the plate to an acidic medium of hydrochloric acid at a concentration of (۱M) in different temperatures. The results revealed that as the temperature increases, the inhibition efficiency decreases.

Keywords:

NHPID , carbon steel , Corrosion Inhibition , Organic inhibitor , thiouria