The inhibitive effect of Limbarda crithmoides (L.) essential oil on the corrosion of mild steel in 1M HCl solution has been investigated by weight loss measurement. The results obtained showed that inhibition efficiency increases with inhibitor concentration to attain 77.85% at 2 g/L of essential oil. The temperature effect on the corrosion behavior of steel in 1M HCl without and with the inhibitor at 2 g/L was studied in the temperature range from 303 and 343 K. The inhibition was assumed to occur via adsorption of the inhibitor molecules on the metal surface. The adsorption of the essential oil components on the mild steel surface obeyed the Langmuir adsorption isotherm. Gibbs free energy of adsorption indicated that the adsorption process is spontaneous and the molecules adsorbed on the metal surface by the process of physical adsorption.

The chemical composition of Senecio inaequidens essential oil was investigated for the first time using Gas chromatography (GC), Gas chromatography/Mass spectrometry (GC/MS) and Nuclear Magnetic Resonance (NMR) after column chromatography (CC). Sixty components accounting for 98.8 % of the oil were identified. Among them, myrcene (21.4 %), (Z)-β-ocimene (17.6 %), α-pinene (12.5 %), limonene (8.1 %) and cacalohastine (6.8 %) are the main components. The inhibitions of the corrosion of mild steel in Hydrochloric acid solution by S. inaequidens essential oil and its CC-fractions have been studied using weight loss measurements. All samples showed promising anticorrossive activity against mild steel in 1M HCl. Inhibition was found to increase with increasing concentration of all samples to attain 90.56 %, 82.54 %, 86.54 % and 87.14 % at 2g/L for S. inaequidens oil, hydrocarbon fraction (HF) and oxygenated fractions (OF and OF1), respectively. The effect of temperature on the corrosion behavior of mild steel in 1 M HCl without and with the S. inaequidens essential oil at 2 g/L was also studied. The inhibition was assumed to occur via adsorption of the inhibitor molecules on the mild steel surface according to the Langmuir adsorption isotherm. The thermodynamic parameters for activation and adsorption processes were calculated and discussed. The results obtained showed that the S. inaequidens essential oil could serve as an environmentally inhibitor of the corrosion of mild steel in Hydrochloric acid media.

Publication de 10 sequences de Teucrium marum - marqueur : chloroplast tRNA-Leu (trnL) gene; trnL-trnF intergenic spacer, complete sequence; and tRNA-Phe (trnF) gene.