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In this study, the two aqueous extracts from the aerial parts of Aaronsohnia pubescens subsp. pubescens (Odorized aqueous extract (OE) and Deodorized aqueous extract (DE)) were used as some novel ecological corrosion inhibitors for mild steel (MS) in 1 M HCl medium. For this reason, the inhibition behavior of the OE and DE were having investigated using weight loss measurements, electrochemical assays, kinetic and thermodynamic parameters, electrochemical methods both stationary (Potentiodynamic polarization (PDP)) and transient (Electrochemical impedance spectroscopy (EIS)). The obtained results showed that EO and DE act as effective corrosion inhibitors and the inhibition efficiency of inhibitors increases for the concentration of 1.5 g/L; reaching some high values of 93.11 and 87.88 % in 1 M HCl solution at 308 K for OE and DE, respectively. Furthermore, PDP measurements exhibited that the studied of each inhibitor performs as a mixed-type inhibitor. The results of the thermodynamic kinetic parameters indicate the adsorption of OE and DE on the MS surface sites obeying the Langmuir adsorption isotherm.

To reduce the use of synthetic compounds as wear-corrosion inhibitors, and substitute them with new ecological compounds, we are interested in evaluating the effect of the essential oils against the tribocorrosion. The present paper describes the effect of adding Thymus zygis subsp. gracilis (TZ) essential oil (3 g·L−1) on AISI 304L tribocorrosion behavior in 0.5 M H2SO4. As a result, the addition of this essential oil decreases the tribocorrosion rate [E (%) = 84.38], the value of friction coefficient, and the energy dissipated during sliding wear, in comparison to those recorded for dry environment and 0.5 M H2SO4. In addition, the essential oil improves the surface morphology of metal as shown by the scanning electron microscopy and energy dispersive X-ray and the three-dimensional optical profiler analysis. In addition, the modeling approaches of experimental results, involving the density functional theory, the electrostatic potential, and the Monte Carlo methods, show that thymol (42.5% of TZ oil) is the best corrosion and tribocorrosion inhibitor that adhered to the stainless steel surface and offers a greater coverage area to block the metal wear-corrosion. According to the obtained results, the TZ essential oil can be used in the food industry to prevent the wear of materials.

The essential oil obtained from the aerial parts of Aaronsohnia pubescens plant (AP oil) was extracted by hydrodistillation, and then, its composition was analyzed by gas chromatography (GC) and GC-mass spectrometry (GC/MS). The corrosion inhibition and adsorption performance of the AP oil on the corrosion mild steel in 1 M hydrochloric acid was evaluated by weight loss analysis, electrochemical methods both stationary [Potentiodynamic polarization (PDP)] and transient [Electrochemical impedance spectroscopy (EIS)]. The weight loss outcomes indicate that AP oil shows a worthy inhibitory efficiency of 83.22% reached at 1.5 g L−1 and 343 K. The charge transfer process mainly controls the results of EIS measurements; PDP measurements showed that the studied AP oil performs as a mixed-type inhibitor. Furthermore, the adsorption on the steel is made according to the Langmuir model. The computational chemistry calculations by density functional theory, the electrostatic potential surface and Metropolis Monte Carlo methods were performed to acquire a greater understanding of adsorption mechanism for each compound among the third major compounds of AP oil on the Fe (110) surface. The finding results exhibited that the E-anethole will be considered as the best inhibitor against mild steel corrosion.

This study was designed to examine the total phenolic and flavonoid levels and the antioxidant activities of the essential oil (EO) and various extracts obtained from fruits of Ammodaucus leucotrichus using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. According to the results obtained, the odorized extracts exhibited stronger antioxidant activity than the desodorized extracts. The highest radical-scavenging activity was shown by the odorized water soluble (OdMW) of the methanol extract (IC50 = 36.7 µg.ml−1), whereas the EO showed the weakest activity potential with an IC50 = 3326.7 µg.ml−1. As well as the radical-scavenging activity of the extracts, they were evaluated in terms of their total phenolic and flavonoid contents. The subfractions of methanol extracts from odorized material were found to be rich in phenolics and flavonoids, followed by the subfractions of desodorized methanol extracts and the hot water extracts. Finally, a positive correlation was observed between the antioxidant activity and total phenolic and flavonoid levels of the extracts.

The analysis of Thymus willdenowii Boiss & Reut essential oils (TW EOs) shows 33 components accounting for (96.3–97.7%) of all identified. The main constituents of TW EOs were thymol (35.5–47.3%), p-cymene (13.9–23.8%), γ-terpinene (8.9–20.3%). The antioxidant assays revealed that all TW EOs tested showed strong activities, the antimicrobial effect of TW EOs has been tested against isolated clinical strains of Proteus mirabilis (ATCC 35659), Escherichia coli (ATCC 25922), Candida albicans (ATCC 10231), Bacillus cereus (ATCC 10876), and Aspergillus brasilliensis (ATCC 16404). The antimicrobial test indicates that TW EOs show an inhibition effect against all the tested bacteria with a MIC of 6.9 to 27.6 μg/mL−1. These results proving that the essential oils extracted from Thymus willdenowii Boiss & Reut may be a new potential source of natural antimicrobial applied in pharmaceutical and food industries.

To investigate biological control methods against post-harvest phytopathogenic fungi in apples, tests on the antifungal activity of essential oil of Melissa officinalis were carried out. The essential oil, obtained by hydrodistillation, was analyzed by gas chromatography coupled with mass spectrometry (GC-MS). Analysis of the essential oil was able to detect 88.7% of the components. The main components are P-mentha-1,2,3-triol (13.1%), P-menth-3-en-8-ol (8.8%), pulegone (8.8%), piperitynone oxide (8.4%) and 2-piperitone oxide (7.3%). The determination of the antifungal activity of the essential oil of M. officinalisis carried out in vitro using the technique of poison food (PF) and the volatile activity test (VA). To carry out these two tests, three phytopathogens that cause the deterioration of apples have been selected: Botrytis cinerea, Penicillium expansum and Rhizopus stolonifer. The overall results of this study suggest that M. officinalis essential oil has potential as a bio-antifungal preservative for the control of post-harvest diseases of apple.

The current study presents for the first time the tribocorrosion behavior of AISI 304L stainless steel in sulfuric acid medium (0.5 M) in the absence and presence of Populus nigra var. italica propolis (PP) essential oil. The results show that in the presence of 600 ppm of PP essential oil a low value of friction coefficient and the dissipated energy are observed, which suggest that the addition of studied essential oil (600 ppm) gives a lubricant aspect to H2SO4 environment. By using the scanning electron microscopy and energy-dispersive X-rays (SEM–EDX), it is clear that the surface is remarkably improved in the presence of P. nigra var. italica propolis essential oil compared to the one exposed to the acid medium without essential oil. From the proprieties of P. nigra var. italica propolis essential oil and the obtained results, it can be suggested that this essential oil is new natural substances that can be used against material wear in aggressive solutions in the presence of a mechanical effect.

2-Allyl-p-mentha-6,8-dien-2-ols P1−P3 synthesized from carvone P are tested as corrosion inhibitors of steel in 1 M HCl using weight loss measurements, potentiodynamic polarisation and impedance spectroscopy (EIS) methods. The addition of 2-allyl-p-mentha-6,8-dien-2-ols reduced the corrosion rate. Potentiodynamic polarisation studies clearly reveal that the presence of inhibitors does not change the mechanism of hydrogen evolution and that they act essentially as cathodic inhibitors. 2-Allyl-p-mentha-6,8-dien-2-ols tested adsorb on the steel surface according to Langmuir isotherm. From the adsorption isotherm some thermodynamic data for the adsorption process are calculated and discussed. EIS measurements show the increase of the charge-transfer resistance with the inhibitor concentration. The highest inhibition efficiency (92%) is obtained for P1 at 3 g/L. The corrosion rate decreases with the rise of temperature. The corresponding activation energies are determined.

Essential oil of aerial parts of Warionia saharae was obtained by hydrodistillation and analyzed by GC and GC-MS. Thirty-nine compounds were identified, accounting for 93.2% of the total oil. β-Eudesmol (34.9%), nerolidol-E (23%), and linalool (15.2%) were the most abundant components. The antifungal activity of the W. saharae oil was tested by poisoned food (PF) technique and the volatile activity (VA) assay against 3 phytopathogenic causing the deterioration for apple. The results indicated that the W. saharae oil inhibited significantly the mycelial growth of all strains tested (p 2 μL/mL in PF technique for all strains. Fungal spore production was completely inhibited at 1 μL/mL air for Alternaria sp. and at 2 μL/mL air for Penicillium expansum and Rhizopus stolonifer.

International audience; The extract (E) and oil of Melissa Officinalis leaves (EO) have been evaluated as a corrosion inhibitors for carbon steel in 1.0 M HCl solution by means of weight loss measurements, potentio dynamic polarization, and electro chemical impedance spectroscopy (EIS). Tafel polarization study revealed that extract (E) and oil of Melissa Officinalis (EO) act as a mixed type inhibitors. The Nyquist plots showed that with increasing the inhibitors concentrations, the charge-transfer resistance increased and the double-layer capacitance decreased, involving increased inhibition efficiency. The inhibition was found to increase with increasing the concentration of the extract (E) and oil of Melissa Officinalis (EO). The values of inhibition efficiency calculated from weight loss, Tafel polarization curves, and EIS were in good agreement. The effect of temperature on the corrosion behaviour of mild steel in 1.0 M HCl with addition of both extract (E) and oil of Melissa Officinalis (EO) was also studied and thermodynamic parameters were determined and discussed.

International audience; Essential oil of aerial parts of Salvia aucheri Boiss. var. mesatlantica was obtained by hydrodistillation and analyzed by GC and GC/MS. The oil was predominated by camphor (49.8%). The inhibitory effect of this essential oil was estimated on the corrosion of steel in 0.5M H2SO4 using electrochemical polarisation and weight loss measurements. The corrosion rate of steel is decreased in the presence of natural oil. The inhibition efficiency was found to increase with oil content to attain 86.12% at 2g/L. Polarisation curves revealed that this oil of Salvia aucheri var. mesatlantica act as mixed type inhibitor with a strong predominance of anodic character. The temperature effect on the corrosion behaviour of steel in 0.5M H2SO4 without and with the inhibitor at 2 g/L was studied in the temperature range from 303and 343 K, the associated activation energy have been determined. The adsorption of oil on the steel surface was found to obey Langmuir's adsorption isotherm.

The essential oil of the aerial parts of Lavandula multifida L., collected in Errachidia region (three samples) in southeast Morocco, was extracted by hydrodistillation and analyzed by GC and GC-MS. The oil was predominated by carvacrol (57.9–59.0%). L. multifida oil was tested as corrosion inhibitor of C38 steel in 0.5 M H2SO4 using weight loss measurements, electrochemical polarization, and EIS methods. The results obtained by measurements of weight loss showed that inhibition efficiency increases with inhibitor concentration to attain 72.2% at 2 g/l of oil at 298 K. Polarization curves revealed that L. multifida oil acts as mixed type inhibitor. The temperature effect on the corrosion behavior of steel in 0.5 M H2SO4 without and with the inhibitor at 2 g/l was studied in the temperature range from 303 and 343 K. The adsorption of inhibitor on the C38 steel surface was found to be a spontaneous process and to obey Langmuir’s adsorption isotherm. The associated activation energy has been determined.

Essential oil from Artemisia herba alba (Art) was hydrodistilled and tested as corrosion inhibitor of steel in 0.5 M H 2 SO 4 using weight loss measurements and electrochemical polarization methods. Results gathered show that this natural oil reduced the corrosion rate by the cathodic action. Its inhibition efficiency attains the maximum (74%) at 1 g/L. The inhibition efficiency of Arm oil increases with the rise of temperature. The adsorption isotherm of natural product on the steel has been determined. A. herba alba essential oil was obtained by hydrodistillation and its chemical composition oil was investigated by capillary GC and GC/MS. The major components were chrysanthenone (30.6%) and camphor (24.4%).

The inhibitive action of pulegone and pulegone oxide toward acid corrosion of steel in molar hydrochloric acid was studied by weight loss measurements, potentiodynamic polarization, and impedance spectroscopy (EIS) methods. The pulegone is extracted starting from oil of Pennyroyal Mint (Mentha pulegium). The natural compound was found to delay the corrosion rate. The pulegone oxide is prepared by oxidation of pulegone. The inhibition efficiency was found to increase with the inhibitor content to attain 81 and 75% at 5 g dm−3 for pulegone and pulegone oxide. The increase in temperature leads to an increase in the inhibition efficiency of the natural compared.

Purpose – This paper seeks to evaluate the effect of natural menthols and their synthesised epoxy‐allylmenthols as a non‐toxic inhibitor on the corrosion of steel in HCl media at various temperatures.Design/methodology/approach – Epoxy‐allylmenthols were synthesised and characterised. Gravimetric technique was used to measure the efficiency of corrosion inhibition.Findings – Modified allylmenthol (to epoxy‐allylmenthol) exhibited a good inhibition. But its efficiency decreases with temperature.Research limitations/implications – The inhibition efficiency increases with the concentration of inhibitor to attain 74 percent at 0.8 g/l.Practical implications – The efficiency of menthol derivatives increases with the concentration but decreases with rise of temperature in the 303‐328 K range. Natural inhibitor can be used in chemical cleaning and pickling processes.Originality/value – The originality of this work is to find a safe and cheap eco‐friendly inhibitor from natural plants.

International audience; There is a growing trend in utilizing plant extracts and pharmaceutical compounds as corrosion inhibitors. Accurate identification of the essential oil of aerial parts of Pelargonium was obtained using hydrodistillation, gas chromatography and gas chromatography–mass spectrometry. The oil was predominated by citronellol (22.8 %). The inhibitory effect of essential oil and extract of Pelargonium was estimated on the corrosion of mild steel in 1 M hydrochloric acid (HCl) using weight loss, electrochemical impedance spectroscopy (EIS) and Tafel polarization curves. Inhibition was found to increase with increasing concentration of the essential oil and extractof Pelargonium. The effect of temperature on the corrosion behavior of mild steel in 1 M HCl with addition of essential oil and extract was also studied, and the thermodynamic parameters were determined and discussed. Values of inhibition efficiency were calculated from weight loss, Tafel polarization curves, and EIS. All results are in good agreement. Polarization curves showed that essential oil and extract of Pelargonium behave as mixed type inhibitors in HCl (1 M). The results obtained showed that the essential oil and extract of Pelargonium could serve as an effective inhibitor of the corrosion of mild steel in HCl solution. To avoid any unexpected toxicity, the majority of compounds have been studied by using POM analyses.

Natural oil extracted from Pennyroyal Mint (Mentha pulegium, PM) was evaluated as corrosion inhibitor of steel in molar hydrochloric using weight loss measurements, electrochemical polarisation and EIS methods. The naturally oil was found to retard the corrosion rate of steel. The inhibition efficiency was found to increase with oil content to attain 80% at 2.76 g/L. PM oil acts as a cathodic inhibitor. The increase in temperature leads to an increase in the inhibition efficiency of the natural substance. The adsorption isotherm of natural product on the steel has been determined.

International audience; The essential oil and the volatile compounds of Salvia aucheri Boiss. var. mesatlantica Maire were analyzed by gas chromatography (GC) and GC-mass spectrometry (GC-MS). The volatile compounds were detected using headspace-solid phase microextraction (HS-SPME) under optimized parameters. A comparative qualitative and quantitative study on the composition of the oils was carried out. For this, 38 compounds, constituting 95.40% of the oil, were identified in the essential oil by hydrodistillation (HD), and 32 compounds, representing 93% of the oil, were characterized by HS-SPME. The major components identified are camphor (49.80%, 51.80%), 1,8-cineole (9.50%, 9.40%), viridiflorol (8.80%, 1.40%), camphene (7.80%, 10.60%), α-pinene (2.90%, 4.50%), and p-cymene (1.50%, 2.40%) of essential oil and volatile compounds detected in HS-SPME, respectively. Quantitative but not qualitative differences have been found in the chemical composition of both analyzed samples depending on the extraction method. For these reasons, HS-SPME can be considered as an alternative technique for isolating volatiles from aromatic plants.

International audience; The essential oil and solvents extract of Ptychotis verticillata have been tested as inhibitors of corrosion of mild steel in 1 M HCl. Measurement of weight loss, electrochemical impedance spectroscopy, and potentiodynamic polarization curves were used to evaluate inhibition of corrosion in 1 M HCl. The efficiency of inhibition was found to increase with increasing inhibitor concentration, because of adsorption of inhibitor molecules on the metal surface; adsorption was in accordance with the Langmuir isotherm. In 1 M HCl the efficiency of inhibition was 74.6 % for 1.08 g/L essential oil rich in phenolic compounds as major compounds (48 %). Efficiency of inhibition, as determined by measurement of weight loss, was 75 and 86 %, respectively, for diethyl ether and ethyl acetate extracts at 0.5 g/L.

International audience; Asteriscus graveolens is an endemic medicinal plant mainly distributed in south-western Algeria and south-eastern Morocco. The essential oils of leaves, stems and flowers of A. graveolens had been studied by GC, GC-MS and 13C NMR. The spectral data of two nerolidol derivatives (6-oxocyclonerolidiol and 6-hydroxycyclonerolidiol) were reassigned using 1D and 2D NMR. These compounds can be considered as chemical markers of this genus. The structure of a monoterpenic diester bearing to the chrysanthenane skeleton (cis-8-acetoxychrysanthenyl acetate) was reported for the first time using GC-MS, 1D and 2D NMR. The stem and leaf oils was characterized by high content of oxygenated sesquiterpenes with 6-oxocyclonerolidol and 6-hydroxycyclonerolidol as major components and the flower essential oils were dominated by the new monoterpenic compound cis-8-acetoxy chrysanthenyl acetate.

International audience; Essential oil from fennel (Foeniculum vulgare) (FM) was tested as corrosion inhibitor of carbon steel in 1 M HCl using electrochemical impedance spectroscopy (EIS), Tafel polarisation methods and weight loss measurements. The results show that the increase of the charge-transfer resistance (Rct) with the oil concentration supports the molecules of oil adsorption on the metallic surface. The polarization plots reveal that the addition of natural oil shifts the cathodic and anodic branches towards lower currents. Such shifts indicate that FM oil acts as a mixed-type inhibitor. The global rate of corrosion estimated by weight loss measurements confirms the above results. The inhibition efficiency attains a maximum of 76 % at 3 mL/L, but decreases with the rise of temperature. The analysis of FM oil, obtained by hydro-distillation, using Gas Chromatography (GC) and Gas Chromatography/Mass Spectrometry (GC/MS) showed that the major components were limonene (20.8 %) and -pinene (17.8%). The adsorption of FM on the steel surface has been discussed according to the chemical composition of the oil, giving an explanation to the obtained results.

The title compound, C18H16N2O, is a new dihydropyridazin-3(2H)-one derivative synthesized in one step by condensation of α-benzylidene-γ-tolylbutenolide with hydrazine. The molecule is not planar; the tolyl and pyridazine rings are twisted with respect to each other making a dihedral angle of 27.35 (9)° and the benzyl ring is nearly perpendicular to the pyridazine ring with a dihedral angle of 85.24 (5)°. In the crystal structure, inversion dimers arise, being linked by pairs of N—H...O hydrogen bonds. Weak C—H...O hydrogen bonds and weak offset π–π stacking stabilize the packing. The π–π stacking occurs between the pyridazine rings of symmetry-related molecules, with a centroid–centroid distance of 3.748 Å, an interplanar distance of 3.605 Å and a slippage of 1.024 Å.

Two diastereoisomers of the title compound, C(25)H(26)N(2)O, have been prepared by cyclo-addition between 1,3,3-trimethyl-2-methyl-eneindoline and C-phenyl-N-phenyl-nitrone. The stereochemistry of the major diastereoisomer, viz. S,R/R,S, is confirmed by the X-ray analysis. The oxazole and the pyrole rings have envelope conformations. The packing is stabilized by weak C-H⋯π inter-actions involving the phenyl ring attached to the N atom of the oxazole and the phenyl ring of the indole fragment.

Evolution of the major spiroadduct obtained by cycloaddition of C,N-diphenylnitrone with 3-methylenephthalide in Zn/3 M HCl media gives a rearrangement product. The reaction did not stop at the formation of an aminoalcohol but was followed by dehydration; the title compound, C22H19NO2, was obtained after hydrogenation. It exists in the diastereoisomer SS/RR form. The packing is stabilized by weak N—H...O and C—H...O hydrogen-bond interactions.