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In this work, a new polyamide (PA) based on thiourea and tartaric acid was synthesized and characterized by FT-IR spectroscopy. The efficiency of the new synthesized compound was evaluated as a corrosion inhibitor for carbon steel in 1 M HCl solution using weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy techniques (EIS). The results show that PA is a good corrosion inhibitor and its inhibition efficiency reaches 90.6% at 250 ppm. The values of the inhibition efficiency calculated from various techniques are in reasonably good agreement. The results obtained from EIS measurements show that the charge transfer resistance (Rt) increases with increasing inhibitor concentration, while the electrochemical double layer capacitance (Cdl) decreases. The inhibition process was attributed to the formation of an adsorbed film that protects the metal surface against corrosive medium. The adsorption of PA on the steel surface was found to obey Langmiur's adsorption isotherm. The mechanism of the adsorption process was discussed in the light of the chemical structure of PA. Scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDX) were used to confirm the existence of such protective film. [ABSTRACT FROM AUTHOR]

Abstract: Polyethylene terephthalate waste (PET) was depolymerized by triethanolamine into glycolyzed product (GT), followed by esterification with bromacetic acid in the presence of manganese acetate as a catalyst to give (GT-Br). The obtained ester was reacted with thiourea to give thiol derivative (GT-SH). The effectiveness of the synthesized compound as corrosion inhibitor for API XL65 carbon steel, in 2M hydrochloric acid solution was investigated by various electrochemical techniques such as open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results of these investigations showed enhancement in inhibition efficiencies with the increasing of inhibitor concentration. The protective film formed on carbon steel surface was analyzed using an energy dispersive X-ray analysis (EDX) technique. Also, scanning electron microscope (SEM) was used to study the surface morphology of steel surface in the absence and presence of 400ppm of the additive. [Copyright &y& Elsevier]

Abstract: The ability of new synthesized non ionic surfactants (I and II) to protect carbon steel in acid chloride solution was investigated using potentiostatic polarization, open circuit potential, weight loss and surface tension measurements. The experimental results showed that these inhibitors revealed a very good corrosion inhibition even at low concentrations. The percentage inhibition efficiency (η%) increases by increasing the inhibitor concentration until the critical micelle concentration (cmc) is reached. It was found that, the adsorption ability of the surfactant molecules on carbon steel surface increased with the increase of the molecular size of the surfactant. Potentiostatic polarization curves indicate that the inhibitors under investigation act as mixed type. Finally, the mechanism of carbon steel dissolution in acidic medium was discussed both in absence and presence of the inhibitor molecules. [Copyright &y& Elsevier]

The anionic surfactant [p-myristyloxy carbonyl methoxy-p′-sodium carboxylate-azobenzene] was prepared. The surface tension at 298 K was measured, the critical micelle concentration (cmc) and some surface active parameters were calculated. The inhibition efficiency (η%) of this surfactant has been studied by both chemical and electrochemical techniques at 25 °C. A significant decrease in the corrosion rate was observed in presence of the investigated inhibitor. The galvanostatic polarization curves showed that, the inhibitor behaves as mixed type but the cathodic effect is more pronounced. Tafel slopes are approximately constant and independent on the inhibitor concentration. The observed corrosion data indicate that, the inhibition of mild steel corrosion is due to the adsorption of the inhibitor molecules on the surface, which follow Langmuir adsorption isotherm. The surface morphology of mild steel samples in absence and presence of the inhibitor was examined using scanning electron microscopy. [Copyright &y& Elsevier]

Two polyesters derivatives of maleic and phthalic anhydride with polyethylene glycol were synthesized and characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD). The efficiency of these compounds as corrosion inhibitors for carbon steel in 1 M HCl, has been determined by gravimetric and electrochemical measurements. Surface morphologies scanning electron microscopy (SEM) and energy dispersion X-ray (EDX) were used to characterize the steel surface. These compounds inhibit corrosion even at very low concentrations in 1 M HCl and the aromatic phthalate derivative showed superior inhibition efficiency than the aliphatic maleate derivative. The polarization curves indicate that the compounds are mixed-type inhibitors, affecting both anodic and cathodic corrosion currents. Adsorption of these compounds on the carbon steel surface is in agreement with the Langmuir adsorption isotherm model. The calculated Gibbs free energy values confirm the chemical nature of the adsorption. [ABSTRACT FROM AUTHOR]

Three trimeric cationic pyridinium surfactants (APMC 6 , APMC 12 and APMC 18), were synthesized via esterification reaction, followed by a quaternization reaction, and characterized by micro-elemental analysis, FTIR, and 1HNMR spectroscopy. Surface-active parameters for APMC compounds were investigated using surface tension measurements. The critical micelle concentration values declined as a function of the alkyl chain length. The corrosion inhibition performance of these surfactants was studied on API 5L X70 carbon steel against oilfield formation water as corrosive medium by various electrochemical techniques. The results indicated that APMC surfactants showed superior corrosion inhibitive activity, as the inhibition efficiency (%I.E.) was up to 94% for APMC 18. Atomic force microscopy confirmed the creation of a protective layer on the carbon steel surface. Furthermore, the anti-scaling aspects of APMC compounds were investigated using static scale precipitation technique. The data revealed that the scale inhibition performance elevated by increasing the dosage of APMC compounds. Both anti-corrosion and anti-scaling results supported the potential multifunctional use of APMC compounds against corrosion and scale problems in formation water. Finally, quantum chemical calculations and Monte Carlo simulations were computed to fulfill a rationale of the obtained experimental data. Unlabelled Image • Three trimeric cationic surfactants (APMC) were synthesized and characterized. • APMC surfactants were good mixed-type corrosion inhibitors for X70 steel protection. • APMC surfactants were good antiscalant against scale tenable formation water. • AFM surface examination confirms the adsorption of APMC surfactants on X70 steel. • Theoretical insilico calculations showed good agreement with experimental data. [ABSTRACT FROM AUTHOR]

One step reaction mechanism was employed to synthesize ethoxylated aminomethylethiazole derivatives characterized by spectroscopic methods (FTIR, 1HNMR and 13CNMR). Gravimetric and electrochemical techniques were employed to evaluate the mitigation efficiency of the as-prepared for X65 carbon steel corrosion in 15% (v/v) HCl. The surface coverage and the inhibition performance were functions in the surfactant type, concentration and temperature. Tafel data indicates that, the 1 × 10−3 M (EO, 12) shows maximum inhibition 95.5% at 25 °C. Inhibitory action of these compounds over X65 obey Langmuir model. SEM and EDX confirm the formation of adsorbed-protective layer over X65 surface. DFT calculations and MC simulations support the obtained experimental data; where, the adsorption ability of EO, 12 is the highest. Image 1 • Newly synthesized ethoxylated surfactant compounds are prepared and evaluated as X65 corrosion inhibitor in 15%(v/v) HCl. • Ethoxylated EO,12 drops the corrosion rate from 8201.8 mpy to 638.6 mpy with efficiency 92.21%. • Surface analysis: SEM and EDX confirm the formation of protective film over X65 surface. • The EO,12 forms a persistent film on X65 surface over 24 h. • DFT calculations and MC simulations support the experimental data. [ABSTRACT FROM AUTHOR]