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The effect of the phenolic (OOMW-Ph) and non-phenolic (OOMW-NPh) fractions of the extract of olive oil mill wastewaters was evaluated as corrosion inhibitor of steel in molar hydrochloric using weight loss measurements and electrochemical polarisation. The results obtained reveal that the referred compounds reduce the corrosion rate. The inhibiting action increases with the concentration of the extract compounds to attain 88.9% and 89.1% of OOMW-Ph and OOMW-NPh, respectively. The increase in temperature leads to a decrease in the inhibition efficiency of the compounds in the temperature range 303 at 333 K. The adsorption isotherm of the inhibitors on the steel surface has been determined. The thermodynamic data of activation and adsorption are determined as well. The phenolic compound (bioactive) most abundant in OOMW extracts is hydroxytyrosol (4 -(2-hydroxyethyl) -1, 2-benzenediol), playing an important role in the effect of the anti-corrosion, either alone or in synergy with other two compounds (tyrosol and oleuropein (4 -(2-hydroxyethyl) phenol) which are present with considerable amounts.

The influence of 2-[3-(2-oxo-2-phenylethylidene)-1,4-dihydroquinoxaline-2(1H)ylidene]-1-phenylethanone (Qx1) and amino-2-aniline (Diam1) on the corrosion of steel in 1 M HCl solution has been investigated by weight loss measurements, potentiodynamic polarisation and impedance spectroscopy (EIS) methods. The inhibiting action increases with the concentration of Qx1 and Diam1. The highest efficiency (85%) is obtained at the 10-4 M Qx1. There is good agreement between gravimetric and electrochemical methods (potentiodynamic polarisation and EIS). Polarisation measurements also show that Qx1 and Diam1 act as mixed inhibitors. The cathodic curves indicate that the reduction of proton at the steel surface happens with an activating mechanism. Qx1 adsorbs on the steel surface according to Langmuir adsorption model. Effect of temperature is also studied between 308 and 353 K.

PurposeThe purpose of this paper is to evaluate the physicochemical properties, fatty acids, tocopherols, and polyphenols of Algerian argan oil.Design/methodology/approachThe argan oil was extracted from the kernel by an organic solvent, the n‐hexane. Several methods and techniques (spectrophotometric, titrimetric, refractometric, and chomrtographic (CPG/high‐performance liquid chromatographic – HPLC) were used to characterise to argan oil.FindingsThe argan oil was yellow oil with faintly marked smell and flavour. The physicochemical analysis showed that the oil was pure, fresh, not siccative and rich in C18 medium chain unsaturated fatty acids, particularly the oleic acid. A HPLC and gaseous phase chromatography methods were developed for the quali‐quantitative analysis of α‐tocopherol and fatty acids composition, respectively.Research limitations/implicationsThis highlight shows that the composition of argan oil is oleic‐linoleic type rich in α‐tocopherol (20 mg/kg). The phenolic fraction known for its antioxidant properties ranges from 30 to 50 mg/kg. The argan oil is mainly rich in antioxidant compounds such as phenolic compounds and α‐tocopherol. Argan oil is rich in unsaturated fatty acids, tocopherol and phenolic compounds.Practical implicationsConsidering its rich composition in antioxidant compounds and essential fatty acid, argan oil has been used for a long time as a food and for body care, prevention and treatment of cardiovascular and some cancers diseases. A deep knowledge of the chemical composition of argan oil will certainly show that is has a high‐nutritional potentiality and is claimed to have favourable medicinal and cosmetic properties.Originality/valueNo such research has been carried out on the argan oil extracted from Argania spinosa (L.) of Algeria. The present work was undertaken to study the physicochemical and nutritional properties of the argan oil.

The inhibition of the corrosion of Mild Steel (MS) in 1 M HCl solution by a new synthesised organic compound, namely 1,1'-(2,2'-(2,2'-oxybis(ethane-2,1-diyl)bis (sulfanediyl))bis(ethane-2,1-diyl))diazepan-2-one, has been studied by weight loss measurements, electrochemical polarisation and electrochemical impedance spectroscopy (EIS). The experimental results have showed that this organic compound revealed a good corrosion inhibition and the inhibition efficiency is increased with the inhibitor concentration to reach 97% at 1 mM. Potentiodynamic polarisation suggested that it is a mixed type of inhibitor. EIS measurements show an increase of the polarisation resistance with the inhibitor concentration and the electrical equivalent circuit is determined. The inhibitor adsorption process on (MS) surfaces obeys the Langmuir adsorption isotherm and the adsorption isotherm parameters (K ads , ∆G ads , ∆H ads and ∆S ads) were determined. The temperature effect on the corrosion behaviour of (MS) in 1 M HCl without and with inhibitor at different concentration was studied in the temperature range from 308 to 353 K and the kinetic parameters activation such as E a , ∆H a and ∆S a were evaluated.

In this work we made a synthesis of two molecules of the same family, the pyrazole 4-(4,5-dihydro-1H-pyrazol-5-yl)-N,N-dimethylaniline D and N,N-dimethyl-4-(3-methyl-4,5-dihydro-1H-pyrazol-5-yl)aniline D10. These two molecules have a good inhibiting activity against the corrosion of mild steel in 1 M HCl. This activity has been confirmed by gravimetric and electrochemical studies; we use a potentiodynamic polarization and the impedance spectroscopic technique. From this investigation, we observe that the integration of a methyl group in the pyrazole D allows decreasing slightly the corrosion of steel. For more information about the action mode of our inhibitors, we launched theoretical calculation by DFT method. We used these calculations to discuss the stability, the reactivity, and the adsorption of our pyrazolic inhibitors with iron in acid medium.

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