The extraction of linseed oil (LO) was realized by refluxing method. The extracted oil was identified by gas chromatography method coupled with mass spectrometry (GC-MS). In order to contribute to the protection of the environment, one contemplates to try on LO as a green corrosion inhibitor. The corrosion inhibition of LO was studied by weight loss and electrochemical methods. The obtained results showed that the LO is an effective inhibitor of the carbon steel corrosion in 1[Formula: see text]M HCl solution, the inhibition efficiency increased with concentration to reach 88% at 200[Formula: see text]ppm. Furthermore, the adsorption of the inhibitor on the surface of metal in 1[Formula: see text]M HCl solution was found to obey Langmuir’s adsorption isotherm. The influences of temperature were also studied in the range from 298[Formula: see text]K to 328[Formula: see text]K. The kinetic and thermodynamic data of activation dissolution process were determined and discussed.

We began, in this work, by the synthesis of the Cu(II) complex with DL-a-alanine which is characterized by powder X-ray diffraction, the UV-visible spectroscopy and the infrared spectroscopy. The RXs show that the complex has the formula C 6 H 12 N 2 O 4 Cu, 2H 2 O while the experimental data show that the ligand is bidentate and the studied complex adopts octahedral stereochemistry. We then studied the inhibitory effect of Bis (DL-a-alaninato) copper dihydrate complex on ordinary steel in 1M HCl solution. The corrosion inhibition study of this complex was carried out by the electrochemical method (stationary and transient). The measurements carried out by this method gave a maximum efficiency of 88% to 10 -5 M of Bis (DL-a-alaninato) copper dihydrate complex on an ordinary steel surface of 1 to 2 cm dimension in the presence of a 1M HCl solution. The obtained results show that the adsorption process of the Bis (DL-a-alaninato) copper dihydrate complex on the metal surface obeys the Langmuir adsorption isotherm.

The effect of hydroxyl group number of some anthraquinon derivatives 1,2,4-trihydroxyanthraquinone (purpurin) and 1,4-dihydroxyanthraquinone (quinizarin) on their corrosion inhibition efficiency has been reported in order to establish a relationship between inhibitor efficiency and molecular structure. Experimental study is based on the potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). On the other hand, the quantum chemistry calculations were performed using B3LYP/6-31G (d) method to determine the electronic and structural parameters of the studied anthraquinon derivatives. The results revealed that the compound containing supplementary group (OH) presents the highest inhibition efficiency (91.5 %) in the case of Purpurin, that value is less than that obtained for Quinizarin (89.0 %). The experimental study indicated that the inhibition efficiency depends on concentration and molecular structure of the investigated compounds. The obtained experimental and theoretical results agree well and confirm that Purpurin, possessing the most number of OH group, is the better inhibitor.