| Metal corrosion is a public nuisance, causing strong economic loss both on steel and petroleum field. Therefore, inhibitors are widely used to protect against corrosion. So far, organic compounds whose molecules include N, O, S, P atoms and multiple bonds are used as the efficient inhibitors by forming strong combination bonds with Fe atoms on the metallic surface. Especially, organic nitrogen-based compounds such as imidazolines, amido-amines and their salt such as quaternary ammonium salt have been successfully used as corrosion inhibitors.N-[2-[(2-aminoethyl) amino] ethyl]-9-octadecenamide had been synthesized in our lab, then tested as effective and economic acid inhibitor for A3steel in acid medium with weight loss method and electrochemical techniques. The results showed that inhibition efficiency increase with increasing of concentrations of AAOA and the inhibition efficiency reaches94%at the concentration of200mg/L. Meanwhile, inhibitor mechanism was studied in this paper. Langmuir isotherm is found to provide the description of the adsorption behavior of AAOA. It can assume the adsorption of inhibitor molecules on metal surface is by chemisorption, which has been understood taking into account some other adsorption parameters (AG0,AH0,AS0) and the activation parameters (Ea, AH’, AS*).The heptadeceny imidazoline was synthesized and optimization scheme was determined by orthogonal test. The inhibition performance of heptadeceny imidazoline in the system of A3steel/1M HCl was studied at different concentrations, temperatures and dipping acid time. SEM photographs showed the surface morphologies of A3steel was flat in the inhibition solutions while it was severe pitted in the blank solutions. All obtained results show this organic compound is a good acid inhibitor.Based on synthesis scheme of heptadeceny imidazoline, quaternary ammonium salt was synthesized in our lab. Its high inhibitor efficiency was tested by compared with other eight kinds of inhibitor existed in market. |
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