Abd El-Aziz S. Fouda

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

SummaryMeasurements 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 (ΔG°ads. andf) are calculated and discussed.ZusammenfassungEs 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 (ΔG°ads.,f) berechnet.

Cluster type molecule as novel corrosion inhibitor for steel in HCl solution

The MOF [Ag (qox) (4-hb)] 1, was obtained at room temperature by the reaction of AgNO3, quinoxaline (qox) and 4-hydroxy benzoate (4-hb). A cluster molecule containing two silver atoms, two qox and two 4-hb ligands is considered the basic building block of the structure of 1. 3D-network structure is created via H-bonds and π-π stacking. The MOF 1 was tested as corrosion inhibitor for carbon steel in 1 M HCl solution using potentiodynamic polarization and electrochemical impedance techniques (EIS). The polarization measurements indicated that the MOF 1 is of mixed type. The adsorption of MOF 1 obeyed Langmuir adsorption isotherm. The inhibition efficiency increased with increase in MOF 1 concentration but decreased with increase in temperature. The activation and thermodynamic parameters were calculated and discussed. Mechanism of inhibition is explained on the basis of molecular structure of the inhibitor.

Synthesis and Structure Characterizations of Coordination Polymers Based on Silver(I) and Nitrogen Donors

Yellow crystals of the coordination polymers (CP) [Ag(qox)NO3], 1 [Ag(pyzca)], 2 were obtained by the reaction of AgNO3, quinoxaline (qox) or pyrazinecarboxylic acid (pyzcaH), respectively. The crystal structure of 1 displays 1D-extended chain of [Ag(qox)]n with NO3 coordinated to every Ag atom. The 1D-chains of 1 are interconnected by strong hydrogen bonds, π–π stacking and short contacts developing two dimensional sheets containing channels. Furthermore, the overall packing arrangement of 1 results 3D topology with corrugated network. The Ag atom in 2 acquires tetrahedral geometry while each pyzca ligand provides three donor sites connected to three Ag atoms. The structure of CP 2 displays 1D-extended helical chain of [Ag(pyzca)]n. The 3D-packing of the CP 2 creates nanometer pores. The luminescence properties of 1 and 2 were discussed.

Corrosion inhibition effect and adsorption of aniline derivatives on QD36 steel surface in acidic solution

Inhibition of QD36 steel corrosion in 0.5 M HCl solution by aniline derivatives was studied using chemical (weight loss), potentiodynamic polarization and electrochemical frequency modulation measurements. The adsorption process of studied aniline derivatives on steel surface obeys the Langmuir adsorption isotherm. The values of activation energy (E*a), adsorption equilibrium constant (Kads), free energy of adsorption (ΔGads°, adsorption enthalpy (ΔHads°) and adsorption entropy (ΔSads°)were calculated and discussed. Potentiodynamic polarization measurements showed that aniline derivatives are mixed-type inhibitors. The results obtained by EFM technique were shown to be in agreement with other chemical and electrochemical techniques. Scaning electron microscope (SEM) was used to study the surface morphology of the QD36 steel in 0.5 M HCl solution in the absence and presence of inhibitors. Further, theoretical calculations were carried out and relations between computed parameters and experimental inhibition efficiency were discussed.

A study on the effect of new prepared amide cationic amphipathic on the corrosion inhibition of API N80 steel pipelines in oil wells industries

Purpose The purpose of this study is to inspect the corrosion inhibition of API N80 steel pipelines in uninhibited solution and inhibited with a synthesized surfactant compound [N-(3-(dimethyl octyl ammonio) propyl) palmitamide bromide] (DMDPP), which is prepared through a simple and applicable method. Design/methodology/approach Weight loss was inspected at five different temperatures of 25°C, 30°C, 40°C, 50°C and 60°C Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation were used at room temperature. Density functional theory was used to study the relation between the molecular structure and inhibition theoretically. Findings Adsorption of the prepared DMDPP fits the Langmuir isotherm model. The inhibition efficiency of the prepared DMDPP amphipathic inhibitor is directly proportional to temperature increase. Polarization results reveal that the investigated DMDPP amphipathic compound behaves as a mixed-type inhibitor. EIS spectra produced one individual capacitive loop. Originality/value The originality is the preparation of cationic surfactants through a simple method, which can be used as corrosion inhibitors in oil production. The synthesized inhibitors were prepared from low-price materials. The work studied the behavior of the synthesized surfactants in inhibiting the corrosion of the steel in an acidic medium. Electrochemical and theoretical studies were presented, besides gravimetric and surface examination.

Sweet Corrosion Inhibition on API 5L-B Pipeline Steel

Corrosion inhibition and adsorption behavior of two triazole derivatives on API 5L-B carbon steel in CO2-saturated 3.5% NaCl solutions was investigated using potentiodynamic polarization, EIS, and EFM techniques. Specimen surfaces were characterized using SEM, EDX, and XRD. Results show that the two compounds are mixed-type inhibitors and inhibition efficiency increases with increasing concentrations. Adsorption of the two compounds chemisorption and obeys Langmuir adsorption isotherm. Activation energy and thermodynamic parameters were calculated. Surface analyses confirm the formation of iron nitrides on the metal surface which supports results obtained from previous techniques.

Structure, Characterizations and Corrosion Inhibition of New Coordination Polymer Based on Cadmium Azide and Nicotinate Ligand

Green crystals of the coordination polymer (CP) [CdN3(en)(n)], 1, was obtained by reaction of CdSO4 · 5H2O with ethyl nicotinate (en) in the presence of NaN3. The structure of the CP 1 was characterized by elemental analysis, IR, 1H-NMR, UV-Visible and X-ray single crystal analysis. The ORTEP plot of CP 1 consists of [(Cd)4(N3)4(en)4(n)4] structure exhibiting 14-atom V-shaped cyclic configuration, which contains 8-atoms ring [(Cd)4(N3)4]. The structure of CP 1 creates 1D-chain where the cyclic structures are connected by two nicotinate ligands (n). The chains are extended in three directions forming 3D-network structure via extensive H-bonds. The CP 1 was tested as corrosion inhibitor for copper in 1 M HCl solution using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results of polarization indicated that CP 1 acts as mixed type inhibitor. Adsorption of CP 1 obeyed Langmuir adsorption isotherm. Effect of temperature on the corrosion process was studied and activation parameters were calculated and discussed. The results obtained from the two different electrochemical techniques are in good agreement.

A new metal-organic framework based on cadmium thiocyanate and 6-methylequinoline as corrosion inhibitor for copper in 1 M HCl solution

Faint green crystals of the metal organic framework (MOF) [Cd(SCN)2(6-mquin)2], 1, was obtained by the reaction of CdSO4.5H2O with 6-methylequinoline (6-mquin) in the presence of KSCN. 3Dnetwork structure was created via H-bonds and π–π stacking interactions. The structure of the MOF 1 was characterized by IR, 1H-NMR, UV-visible, TGA, and X-ray single crystal analysis. The structure of the MOF 1 consists of cyclic (CdSCN)n building blocks exhibiting chair conformation creating 1D-chain decorated by the coordinated 6-mquin on both sides. The 1D zig-zagchain is bonded to another chain by hydrogen bonds organizing these chains into a 2D layer. Furthermore, the 2D layers are interacted each other feathering three-3D metal organic framework containing cavities through face-to-face π···π interactions. The MOF 1 was tested as corrosion inhibitor for copper in 1 M HCl solution using potentiodynamic polarization and electrochemical impedance (EIS) techniques. Adsorption of the MOF 1 obeyed Langmuir adsorption isotherm. Effect of temperature on the corrosion process was studied and the activation parameters were calculated and discussed. The results obtained from the two different electrochemical techniques are in a good agreement.