The use of acid solution during pickling and industrial cleaning leads to corrosive attack on mild steel. Acid solutions are widely used for different applications in industries such as pickling, acid cleaning of boilers, descaling and oil well acidizing. Hydrochloric and sulfuric acids are the most common types of corrosive acids used in such industrial operations .
Organic compounds are usually used to protect metal against corrosion as inhibitors in acidic media. The efficiency of an organic compound as a successful inhibitor is mainly dependent on its ability to get adsorbed on the metal surface. most organic inhibitors adsorb on the metal surface by displacing water molecules on the surface and forming a compact barrier. Heteroatoms, such as sulfur, phosphorus, nitrogen, and oxygen, together with aromatic rings in inhibitor structure are the major adsorption centers. The planarity and the lone electron pairs in the heteroatoms are also important features that determine the adsorption of molecules on the metallic surface –.
unfortunately most of the corrosion inhibitors used for the control of steel corrosion in acidic mediums are toxic and environmentally hazardous materials. In recent years researchers have paid attention to the development of drugs as inhibitors for metallic corrosion. The choice of some of the drugs used as corrosion inhibitors is based on the following facts: a) the molecules have oxygen, nitrogen, and sulfur as active centers, b) they are healthy and reportedly very important in biological reactions (i.e., not hazardous and environmentally friendly), and c) they can be easily produced and purified, , .
According to literature imidazole and thiazole derivatives have shown good corrosion inhibiting in acidic media –. Therfore in this study an imidazothiazole derivative was chosen for investigating it’s corrosion inhibition properties in acidic media. Levamisole, marketed as the hydrochloride salt is an anthelminthic drug belonging to a class of synthetic imidazothiazole derivatives. Levamisole hydrochloride is the commercial name of (S)-6-Phenyl-2,3,5,6-tetrahydroimidazo[2,1-b] thiazole hydrochloride (Figure1).
To the best of our knowledge Levamisole hydrochloride (LMH) has not been used as corrosion inhibitor. Thus, the present study aims at determining the effectiveness of Levamisole hydrochloride as a corrosion inhibitor by gravimetric method as well as AFM techniques.
The possible mechanisms for chemisorption can be attributed to donor–acceptor interactions between the p-electrons of the aromatic systems and the unshared electrons pairs of the heteroatoms (N,S) to form a bond with the vacant d orbitals of the iron atom on the metal surface, which act as a Lewis acid, leading to the formation of a protective chemisorbed layer. In hydrochloric acid medium, inhibitor molecules exist as protonated species and it is assumed that Cl- ions are first adsorbed on...