Phenyl semicarbazide derivatives as corrosion inhibitors for aluminium in hydrochloric acid solution

Summary Measurements of the corrosion rate of aluminium in 2N HCl at 27°C with and without addition of phenyl semicarbazide derivatives (10^–3–10^–5 mol/l) were performed. The adsorption of these compounds was elucidated. Results show that phenyl semicarbazide derivatives are adsorbed on the aluminium surface according to the Frumkin isotherm. From the adsorption isotherm some thermodynamic data for the adsorption process (G° _ads . andf) are calculated and discussed.

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Phenylsemicarbazide als Korrosionsinhibitoren für Aluminium in salzsauren Lösungen

Zusammenfassung Es wurden Messungen der Korrosionsgeschwindigkeit von Aluminium in 2N HCl bei 27°C mit und ohne Zusatz von Phenylsemicarbaziden (10^–3–10^–5 mol/l) durchgeführt. Es wurde die Adsorption dieser Verbindungen untersucht, wobei sich zeigte, daß die Adsorption der Phenylsemicarbazidderivate der Frumkin-Isotherme gehorcht. Aus der Isotherme wurden einige thermodynamische Parameter des Adsorptionsprozesses (G° _ads. ,f) berechnet.

     

Some aromatic hydrazone derivatives as inhibitors for the corrosion of C-steel in phosphoric acid solution

The effect of furfural benzoylhydrazone and its derivatives (I-VII) as corrosion inhibitors for C-steel in 1M phosphoric acid solution has been studied by weight-loss and galvanostatic polarization techniques. A significant decrease in the corrosion rate of C-steel was observed in the presence of the investigated inhibitors. This study revealed that, the inhibition efficiency increases with increasing the inhibitor concentration, and the addition of iodide ions enhances it to a considerable extent. The effect of temperature on the inhibition efficiency of these compounds was studied using weight-loss method. Activation energy (E(a)*) and other thermodynamic parameters for the corrosion process were calculated and discussed. The galvanostatic polarization data indicated that, the inhibitors were of mixed-type, but the cathode is more polarized than the anode. The adsorption of these compounds on C-steel surface has been found to obey Frumkin's adsorption isotherm. The mechanism of inhibition was discussed in the light of the chemical structure of the undertaken inhibitors.     

Synthesis and evaluation of bipyrazolic derivatives as inhibitors of corrosion of C38 steel in molar hydrochloric acid

Methyl 2-(bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)amino) acetate, BT36, and methyl 2-(bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)amino)-3-(1H-indol-3-yl)propanoate, BT 43, have been synthesized. Investigation by weight-loss measurement and use of electrochemical techniques revealed the compounds are very effective inhibitors of corrosion of C38 steel in 1 M HCl solutions—percentage protection exceeded 95 % for BT43 at concentrations as low as 10^?2 M. An impedance study in the absence and presence of these compounds revealed the mechanism of protection was cathodic inhibition by polarization and charge-transfer. The Langmuir adsorption isotherm was obeyed. Quantum chemical data calculated by use of DFT at the B3LYP/6-31G* level of theory revealed a good correlation between inhibition efficiency and the molecular structure of BT36 and BT43. The highest occupied molecular orbital, the lowest unoccupied molecular orbital, the separation energy (ΔE), and the dipole moment (μ) from the inhibitor to the metal surface explain the experimental data well.     

Schiff’s bases as inhibitors of mild steel corrosion in hydrochloric acid

Mass loss and thermometric methods are used to study the inhibition of corrosion of mild steel in hydrochloric acid by Schiff’s bases N-(furfurlidine)-4-methoxy aniline, N-(furfurlidine)-4-methylaniline, N-(salicylidine)-4-methoxy aniline, N-(cinnamalidine)-4-methoxy aniline, and N-(cinnamalidine)-2-methylaniline. Results of inhibition efficiency yielded by the two methods are in good agreement and depend on the inhibitor and acid concentration. Maximum inhibition efficiency is 98%. The efficiency increases with the inhibitor concentration and acid strength. Published in Russian in Elektrokhimiya, 2007, Vol. 43, No. 2, pp. 252–256. The text was submitted by the authors in English.     

Allylacetylenes and their derivatives as inhibitors of steel corrosion in sulfuric acid

New functionalized derivatives of allylacetylenes were prepared, and their ability to inhibit corrosion of St.3 low-carbon steel in 5 N sulfuric acid was studied. The effectiveness of inhibition of steel corrosion was studied in relation to the structure of acetylene derivatives, their concentration, and temperature of acidic medium.     

Inhibiting effects of benzamide derivatives on the corrosion of mild steel in hydrochloric acid solution

The inhibition effect of new heterocyclic compounds, namely N-(cyanomethyl)benzamide (BENZA) and N-[(1H-tetrazol-5-yl)methyl]benzamide (BENZA-TET), on mild steel corrosion 1 M HCl was investigated using electrochemical measurements. The results indicated that the inhibition efficiency depends on concentration, immersion time and temperature. The BENZA is a better inhibitor than BENZA-TET. Polarization measurements showed that the inhibitor BENZA-TET is a cathodic type, but BENZA acts as a mixed type inhibitor. In addition, the changes in impedance parameters indicated that these compounds adsorbed on the metal surface leading to the formation of a protective film. Adsorption of benzamide derivatives on the mild steel surface was investigated to consider basic information on the interaction between the inhibitors and the metal surface. It was found to obey the Langmuir adsorption isotherm. From the temperature dependence, the activation energy in the presence of (BENZA) was found to be inferior to that in uninhibited medium. In order to explain why BENZA is the most efficient inhibitor, quantum chemical calculations were applied. The relationships between quantum chemical parameters and corrosion inhibition efficiency have been discussed to see if there is any correlation between them.     

Synthesis diacetylenic ethers with terminal acetylenic bonds and studying them as inhibitors of steel corrosion in hydrochloric acid

New diacetylenic ethers with terminal acetylenic bonds were synthesized.     

Adenosine as corrosion inhibitor for mild steel in hydrochloric acid solution

Research on Chemical Intermediates - (2R,3R,4S,5R)-2-(6-amino-9H-purin-9-yl)-5-(hydroxymethyl)oxolane-3,4-diol (adenosine) is an identified component present in agarwood leaf extract. The corrosion...     

Azorhodanine derivatives as inhibitors for acidic corrosion of nickel

Azorhodanine derivatives (HL1-HL5) were tested as corrosion inhibitors for nickel in 2M HNO3 solution using weight loss and galvanostatic polarization techniques. The results showed that these derivatives act as inhibitors for nickel in this medium. The inhibition was assumed to occur via adsorption of the inhibitor molecule on the metal surface. Polarization measurements indicated that these compounds act as mixed-type inhibitors, but the cathode is more polarized when an external current was applied. This means that these compounds retard the rate of hydrogen evolution and the rate of dissolution of the metal. Results showed that azorhodanine derivatives are adsorbed on the nickel surface following Temkin's adsorption isotherm. The activation energy and thermodynamic parameters were calculated and discussed at different temperatures (30-45 degrees C).     

Electrochemical investigation of corrosion and corrosion inhibition of iron in hydrochloric acid solutions

The inhibition effect of 1-methyl pyrazole (MPA) on the acidic corrosion of iron in 1.0 M HCl was studied at different concentrations (10^?3–10^?2 M) by potentiodynamic polarization and electrochemical impedance spectroscopy, and EIS measurements. It is found from the polarization studies that methyl pyrazole (MPA) behaves mainly as anodic inhibitor in HCl. Values of polarization resistance (R_p) and double layer capacitance (C_dl) in the absence and presence of MPA in 1.0 M HCl are determined. The adsorption of MPA on iron surface from HCl is found to obey Temkin adsorption isotherm.     

The effect of 2-aminoquinoline-6-carboxylic acid on the corrosion behavior of mild steel in hydrochloric acid

The inhibitive effect of 2-aminoquinoline-6-carboxylic acid (AQC) against mild steel corrosion in 1?M HCl solutions was investigated using conventional weight loss, potentiodynamic polarization, linear polarization and electrochemical impedance spectroscopy methods. The weight loss results showed that AQC is an excellent corrosion inhibitor since its efficiency increased with the concentration to attain 91.8?% at 500?mg?l^?1. Electrochemical polarization measurements revealed that AQC acted as a mixed-type inhibitor and the results of electrochemical impedance spectroscopy have shown that the change in the impedance parameters, charge transfer resistance and double layer capacitance, with the change in concentration of the inhibitor is due to the adsorption of the molecule leading to the formation of a protective layer on the surface of mild steel. The adsorption was assumed to occur on the steel surface through the active centers of the molecule. The inhibition action of AQC was discussed in view of Langmuir adsorption isotherm. Density functional theory calculations of quantum parameters were used to explain efficiency in relation with molecular structure.     

Cocos nucifera L. water as green corrosion inhibitor for acid corrosion of aluminium in HCl solution

<正>The ability of Cocos nucifera L.water(CW) as non-toxic corrosion inhibitor for acid corrosion of aluminium in 0.5 mol/L HCl has been studied using chemical technique.CW shows significant inhibition as corrosion inhibitor,with 93%efficiency at the highest concentration of the inhibitor.The inhibitive action is attributed to the adsorption of the inhibitor molecules on metal surface following Langmuir adsorption isotherm.     

Green synthesis,electrochemical, and DFT studies on the corrosion inhibition of steel by some novel triazole Schiff base derivatives in hydrochloric acid solution

In this work, three triazole Schiff base derivatives 1-((1H-1,2,4-triazol-3-ylimino)methyl)naphthalen-2-ol (TMN), N-(furan-2-ylmethylene)-1H-1,2,4-triazol-3-amine (FTA) and N-(thiophen-2-ylmethylene)-1H-1,2,4-triazol-3-amine (TTA) were synthesized under ultrasonic irradiation and were investigated as corrosion inhibitors. FT-IR, NMR, and elemental analysis were used to elucidate the chemical structure of the synthesized inhibitors. The inhibitive characteristics of these inhibitors on C-steel corrosion in 1.0 M HCl were studied using three different techniques. The applied techniques were Electrochemical frequency modulation, electrochemical impedance spectroscopy, and potentiodynamic polarization curves. The acquired data from the experimental methods showed that the optimal concentration for TMN, FTA, and TTA is 1.0 × 10^?3 mol/L, and the inhibition efficiency reached up to 91.68%, 88.44%, and 87.29% for TMN, TTA, and FTA, respectively. Experiments also indicated that these compounds act as mixed-type inhibitors, and their concentration affects the inhibition efficiency in a directly proportional manner. Quantum paraments obtained from density functional theory (DFT) showed good agreement between experimental and computational results.     

Scanning electrochemical microscopy for the investigation of corrosion inhibition of triazino-benzimidazole-2-thiones in hydrochloric acid solution

Aryl-triazino-benzimidazole-2-thiones were synthesized via three-component reaction between ammonium thiocyanate, benzoyl chlorides, and 2-aminobenzimidazole in acetone. The structure of the products was confirmed by NMR, FT‐IR, and mass spectrometer. The corrosion behaviors of these compounds on carbon steel in 2 M HCl solution were investigated by scanning electrochemical microscopy, operated in the substrate-generation/tip-collection mode using Fe²⁺/Fe³⁺ redox couple as redox mediator. The tip current values and local ferrous ion concentrations were obtained. The inhibition efficiency of the inhibitors was investigated by weight loss measurements. When the inhibition efficiency was more than 85 %, scanning electrochemical microscopy and weight loss measurements were in good agreement.     

Nile Blue and Indigo Carmine organic dyes as corrosion inhibitor of mild steel in hydrochloric acid

The inhibiting behavior of Nile Blue and Indigo Carmine organic dyes on mild steel corrosion was evaluated in 1 M HCl solution, separately, by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy techniques. Results show that the inhibition efficiency (%IE) increases with the increasing concentration of Indigo Carmine up to 9.65 × 10⁻⁰⁵ M (%IE ~ 98) and Nile Blue up to 1.08 × 10⁻⁰⁴ (%IE ~ 75–80). Good agreement was found between the results obtained from the different techniques used. Polarization curves indicate that the inhibition of the both inhibitors is of a mixed anodic–cathodic nature, and Langmuir isotherm is found to be an accurate isotherm describing the adsorption behavior. The inhibition mechanism of the inhibitors involves chemisorption interaction between the inhibitor and the mild steel. The inhibition efficiency for both inhibitors decreased by the rising temperature in the range of 25–55 °C, and these results verified the chemisorption behavior of both the inhibitors.     

Amino acids and their derivatives as corrosion inhibitors for metals and alloys

In the last two decades, research in the field of corrosion inhibitors had been directed toward the goal of using cheap effective molecules of low or non-negative environmental impact to replace the environmentally hazardous compounds. One of the encourager compounds which can be used as safe corrosion inhibitors are amino acids. They are environmentally friendly, non-toxic, biodegradable and relatively cheap. On other hand, the development of computational modeling helps to understand the inhibition mechanism of those compounds and to develop the newly designed inhibitors. In this review, most of contribution made in literature on the use of amino acids and their derivatives as corrosion inhibitors for metallic alloys materials were presented and discussed.     

Comparative inhibition study of mild steel corrosion in hydrochloric acid by new class synthesised quinoxaline derivatives: part I

7-Cchloro-3-(4-methoxystyryl)quinoxalin-2(1H)-one (CMOSQ) and 7-chloro-2-(4-methoxyphenyl)thieno(3.2-b)quinoxaline (CMOPTQ) have been investigated for mild steel corrosion in 1 M HCl at different concentrations using weight loss measurements, potentiodynamic polarization curves and electrochemical impedance spectroscopy methods. Generally, inhibition efficiency of the investigated compounds was found to depend on inhibitor concentration and their structures. Comparitive results showed that CMOPTQ was the best inhibitor and the inhibition efficiency increased with increasing the concentration and attained 86 and 87 % at 10^?3 M of CMOPTQ and 10^?3 M of CMOSQ, respectively. Potentiodynamic polarization studies clearly reveal that these inhibitors act essentially as cathodic-type inhibitors. The inhibition efficiency increases with immersion time and reaches 95 % CMOPTQ at 24 h. The electrochemical impedance spectroscopy result showed that these compounds act by formation of film.