Pyrimidine derivative as eco-friendly corrosion inhibitor for nickel−aluminum bronze in seawater

A pyrimidine derivative,6-phenyl-2-thiouracil(PT),was synthesized for developing a corrosion inhibitor(CI)applied in the protection of the nickel−aluminum bronze(NAB)in seawater.The anti-corrosion effect of PT was evaluated by the mass loss experiment,electrochemical tests and surface analysis.The results show that PT exhibits excellent inhibition performance and the maximum inhibition efficiency of PT reaches 99.6%.The interaction mechanism was investigated through X-ray photoelectron spectroscopy(XPS)and molecule dynamics simulation based on the density functional theory(DFT).The S-Cu,Al-N and Cu-N bonds are formed by the chemical interactions,leading to the adsorption of PT on the NAB surface.The diffusion of corrosive species is hindered considerably by the protective PT film with composition of(PT-Cu)_(ads)and(PT-Al)_(ads)on the PT/NAB interface.The degree of suppression is increased with the addition of more PT molecules.

Calcium titanate corrosion inhibitor enabling carbon as inert anode for oxygen evolution in molten chlorides

The corrosion inhibition efficacy of titanate(CaTiO_(3))for carbon anodes in molten salts was investigated through various analytical techniques,including linear sweep voltammetry,X-ray diffraction,scanning electron microscopy,and energy dispersion spectroscopy.The results demonstrate that the addition of CaTiO_(3)corrosion inhibitor efficiently passivates the carbon anode and leads to the formation of a dense CaTiO_(3)layer during the electrolysis process in molten CaCl_(2)-CaO.Subsequently,the passivated carbon anode effectively undergoes the oxygen evolution reaction,with an optimal current density for passivation identified at 400 m A/cm^(2).Comprehensive investigations,including CaTiO_(3)solubility tests in molten CaCl_(2)-CaO and numerical modeling of the stability of complex ionic structures,provide compelling evidence supporting“complexation-precipitation”passivation mechanism.This mechanism involves the initial formation of a complex containing TiO_(2)·nCaO by CaTiO_(3)and CaO,which subsequently decomposes to yield CaTiO_(3),firmly coating the surface of the carbon anode.In practical applications,the integration of CaTiO_(3)corrosion inhibitor with the carbon anode leads to the successful preparation of the FeCoNiCrMn high-entropy alloy without carbon contamination in the molten CaCl_(2)-CaO.

Expired drugs as vapor-phase corrosion inhibitors of copper in simulated marine atmospheric environment

Urea,paracetamol and glutamine(based on the expired drugs)were selected as vapor-phase corrosion inhibitors(VCIs)to study their corrosion protection effect on red copper in simulated marine atmospheric environment by using weight loss,electrochemical measurement techniques(specially designed electrochemical testing device for simulating marine atmospheric environments)and surface morphology characterization analysis(SEM/EDS,XRD,RAMAN,XPS).Weight loss results show that the three corrosion inhibitors have good corrosion inhibition effect on red copper,and the corrosion inhibition efficiency in the order of glutamine(83.62%)>urea(68.46%)>paracetamol(61.47%).Surface morphology characterization analysis provides evidence of adsorption of corrosion inhibitors molecules on the red copper surface,thus forming a protective film that blocked the red copper surface from the aggressive chloride ion attack.

Inhibition of angiogenesis and HCT-116 xenograft tumor growth in mice by kallistatin

AIM： TO investigate the inhibitory effect of kallistatin （KAL） on angiogenesis and HCT-116 xenograft tumor growth.METHODS： Heterotopic subcutaneous injection of 2 Seven days later, 2 x 1011 injected intratumorally （n tumors were induced by x 106 HCT-11 cells in mice. rAAV-GFP or rAAV-KAL was = 5 for each group）. The mice were sacrificed at d 28, by which time the tumors in the rAAV-GFP group had grown to beyond 5% of the total body weight. Tumor growth was measured by calipers in two dimensions. Tumor angiogenesis was determined with tumor microvessel density （MVD） by immunohistology. Tumor cell proliferation was assessed by Ki-67 staining.RESULTS： Intratumor injection of rAAV-KAL inhibited tumor growth in the treatment group by 78% （171 ＋ 52 mm^3） at d 21 after virus infection compared to the control group （776 ＋ 241 mm^3）. Microvessel density was significantly inhibited in tumor tissues treated with rAAV-KAL, rAAV-KAL also decreased the proportion of proliferating cells （Ki-67 positive cells） in tumors compared with the control group.CONCLUSION： rAAV-mediated expression of KAL inhibits the growth of colon cancer by reducing angiogenesis and proliferation of tumor cells, and may provide a promising anti-angiogenesis-based approach to the treatment of metastatic colorectal cancer.

Histone deacetylase inhibitor MS-275 alone or combined with bortezomib or sorafenib exhibits strong antiproliferative action in human cholangiocarcinoma cells

AIM: To investigate the antiproliferative effect of the histone deacetylase (HDAC) inhibitor MS-275 on cholangiocarcinoma cells alone and in combination with conventional cytostatic drugs (gemcitabine or doxorubicin) or the novel anticancer agents sorafenib or bortezomib. METHODS: Two human bile duct adenocarcinoma cell lines (EGI-1 and TFK-1) were studied. Crystal violet staining was used for detection of cell number changes. Cytotoxicity was determined by measuring the release of the cytoplasmic enzyme lactate dehydrogenase (LDH). Apoptosis was determined by measuring the enzyme activity of caspase-3. Cell cycle status reflected by the DNA content was detected by flow cytometry.RESULTS: MS-275 treatment potently inhibited the proliferation of EGI-1 and TFK-1 cholangiocarcinoma cells by inducing apoptosis and cell cycle arrest. MS-275-induced apoptosis was characterized by activation of caspase-3, up-regulation of Bax and down-regulation of Bcl-2. Cell cycle was predominantly arrested at the G1/S checkpoint, which was associated with induction of the cyclin-dependent kinase inhibitor p21Waf/CIP1. Furthermore, additive anti-neoplastic effects were observed when MS-275 treatment was combined with gemcitabine or doxorubicin, while combination with the multi-kinase inhibitor sorafenib or the proteasome inhibitor bortezomib resulted in overadditive anti-neoplastic effects.CONCLUSION: The growth of human cholangiocarcinoma cells can be potently inhibited by MS-275 alone or in combination with conventional cytostatic drugs or new, targeted anticancer agents.

Anodising of 2024-T3 aluminium alloy in electrolyte of sulphuric-boric-phosphoric mixed acid containing cerium salt as corrosion inhibitor

The effect of cerium salt as an inhibitor in anodising of the2024-T3aluminium alloy was studied.Scanning electronmicroscopy equipped with energy dispersive X-ray spectroscopy was used to study the surface composition of the alloy before andafter surface preparation.A mixed electrolyte of10%sulphuric acid,5%boric acid and2%phosphoric acid containing0.1mol/Lcerium sulphate salt was used as the anodising electrolyte.Sealing treatment was also done in boiling water and molten stearic acid.Electrochemical impedance spectroscopy and salt spray techniques were performed in order to investigate the corrosion behaviourand durability of the oxide films,respectively.It was concluded that the presence of cerium ions in anodising electrolyte resulted inthe increase in homogeneity,the rate of oxide film growth and also the thickness of the oxide layer,owing to the high oxidisingpower of cerium ion.

Adsorption isotherm and inhibition effect of a synthesized di-(m-Formylphenol)-1,2-cyclohexandiimine on corrosion of steel X52 in HCl solution

The potential of di-(m-Formylphenol)-1,2-cyclohexandiimine as an environmentally friendly corrosion inhibitor for steel was investigated in 1 mol/L HCl using potentiodynamic polarization, electrochemical impedance spectroscopy and chronoamperometry measurements. All electrochemical measurements suggest that this compound is an excellent corrosion inhibitor for mild steel and the inhibition efficiency increases with the increase in inhibitor concentration. The effect of temperature on the corrosion behavior of mild steel with the addition of the Schiff base was studied in the temperature range from 25 °C to 65 °C. It is found that the adsorption of this inhibitor follows the Langmuir adsorption isotherms. The value of activation energy and the thermodynamic parameters such as ΔHads, ΔSads, Kads and ΔGads were calculated by the corrosion currents at different temperatures using the adsorption isotherm. The morphology of mild steel surface in the absence and presence of inhibitor was examined by scanning electron microscopy(SEM) images.

Effect of Schiff base as corrosion inhibitor on AZ31 magnesium alloy in hydrochloric acid solution

Schiff base derived from the condensation reaction of analar grade 1-amino-2-naphthol 4-sulphonic acid with cinnamaldehyde was prepared under microwave condition.The Schiff base was analysed by infrared spectroscopy.This Schiff base as a corrosion inhibitor of AZ31 magnesium alloy in 0.05 mol/L HCl solution was studied.The inhibition effect of the Schifif base compound（4Z）-4-（3-phenyl allylidene amino）-3-hydroxy naphthalene-1-sulfonic acid（AC） on AZ31 magnesium alloy corrosion was studied using mass loss,potentiodynamic polarization technique,electrochemical impedance spectroscopy methods.The potentiodynamic polarization curve shows that Schiff base AC inhibits both anodic and cathodic reactions at all concentration,which indicates it is a mixed type inhibitor.EIS results indicate that as the additive concentration is increased,the polarization resistance increases whereas double-layer capacitance decreases.The adsorption of AC on the AZ31 magnesium alloy surface in 0.05 mol/L HCl obeys the Langmuir adsorption isotherm.

Corrosion resistance improvement of Ti-6Al-4V alloy by anodization in the presence of inhibitor ions

Colorful thin oxide films were synthesized by galvanostatic anodization on Ti−6Al−4V alloy.Three different aqueous solutions containing corrosion inorganic inhibitors(Na_(2)MoO_(4),NaH_(2)PO_(4) and NH4VO3)were employed for the anodization treatment.The effect of inhibitor anions on the corrosion behavior of the alloy in Ringer solution was studied.Open circuit potential(OCP),Tafel polarization,linear sweep voltammetry(LSV)and chronoamperometry(CA)were performed to evaluate the corrosion performance of the treated electrodes.The incorporation of the inhibitor ions was detected by the release of Mo,V and P through ICP-AES technique.The formed oxides were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).The results show that compact,amorphous oxides without pores or cracks were obtained independently of the solution used.The sample anodized in Na_(2)MoO_(4) solution registered the lowest corrosion current density(0.11μA/cm^(2)),and it was able to protect the alloy even after 168 h of immersion in Ringer solution.No cracks or corrosion products were detected.The XPS analysis reveals the incorporation of molybdenum to the oxide film in the form of Mo^(6+) and Mo^(4+).

Effects of Corrosion Inhibitors on Lubrication Performance of Rolling Oil for Copper Foil

The 2,5-bis（ethyldisulfanyl）-l,3,4-thiadiazole （T561）, benzotriazole （BTA）,1-N, N-bis （2-ethylhexyl） aminomethyl-4-methyl-lh-benzotriazole （IRGAMET39） and I-IN, N-bis （2-ethylhexyl） aminomethyl] methyl benzotriazole （TT- LX） have been evaluated as corrosion inhibitors used in rolling oil for cold rolling of copper foil. The MRS-10A four-ball friction and wear tests have been carried out to compare their tribological properties, and the lubricating performance of rolling oils has been studied through rolling experiments. The oil sample containing IRGAMET 39 has the same PB value as that one containing T561, with the coefficient of friction increased by 35.6% and wear scar diameter decreased by 4%. The minimum rolling gauge has been studied after rolling lubrication, but the results show that inhibitors have no effect on it. Scanning electron microscopy （SEM） and energy dispersive spectrometry （EDS） analyses have indicated that the inhibitor is adsorbed on the copper surface to prevent copper from being corroded easily. In addition, the LEXT OLS4000 laser confocal microscopy has been used to observe the foil surface which shows that the streaks of foil surface are clear, the scratches are shallow and the surface failure is improved effectively.

Synergistic effect of CeCl3 and benzotriazole on corrosion resistance of naturally aged and artificially aged AA2024 aluminium alloy

The corrosion behaviours of naturally aged and artificially aged AA2024 aluminium alloys in 0.5 mol/dm3 NaCl solution in the presence of environmentally friendly corrosion inhibitors of 10 mmol/dm3 CeCl3, 10 mmol/dm3 BTA and the inhibitor mixture (5 mmol/dm3 CeCl3 + 5 mmol/dm3 BTA) were analyzed. The goal of this work was to determine the level of the synergistic effect of the inhibitor mixture and to explain the nature of this effect. Corrosion properties of the inhibitor layer were studied using the electrochemical impedance spectroscopy (EIS), while the resistance to pit formation and pit growth was studied by applying potentiodynamic polarisation tests. The results of scanning electron microscopy (SEM/EDS) showed that the size of pits formed in naturally aged aluminium alloy was smaller than that formed in artificially aged alloy. The synergistic effect of the inhibitor mixture on corrosion properties of naturally aged alloy was observed throughout 96 h, and in later phases of testing of artificially aged alloy. The synergistic effect of the inhibitor mixture was not noticed on pit formation and pit growth.

Performance of water-based foams affected by chemical inhibitors to retard spontaneous combustion of coal

The micelle generating process of the sodium dodecyl sulfate(SDS) solution with the addition of chemical inhibitors was elucidated using phase separation model, and the descending order of the capacity for the selected chemical inhibitors to reduce the critical micelle concentrations of the solution are Mg Cl_2, Ca Cl_2,NH_4HCO_3 and NH_4Cl. The data to quantitatively describe the foam decay process, including foaming ratio,foam life and decay behaviors, was obtained by pressure measuring system. The results indicate that chemical inhibitors can improve the solution foamability. The capacity of the inhibitors to enhance the solution foamability is sorted as NH_4 Cl, NH_4HCO_3, Mg Cl2 and Ca Cl_2 which can distinctly improve the foam stability as well. The capacity of the inhibitors to enhance the SDS foam stability can be arranged as Mg Cl_2, NH_4 Cl, NH_4HCO_3 and Ca Cl_2. It is observed that the gravity drainage plays a leading role in the increase of proportion of diffusion drainage. The oxidation dynamic parameters of the coal samples treated by inhibition foams were investigated using thermal analysis technique, and their synergistic effects on inhibiting coal oxidation were explored.

Veratraldehyde as Corrosion Inhibitor for Mild Steel in Different Acid Medium

Veratraldehyde was tested as a corrosion inhibitor for mild steel in I M HCI and 0.5 M H2SO4 separately using mass loss and electrochemical studies. The inhibition efficiencies were evaluated at different concentrations of the inhibitor at different temperatures. The inhibition efficiency increased with increase in inhibitor concentration and decreased with increase in temperature in both the acid solutions. Electrochemical studies showed that the inhibitor is of mixed type with a slight predominance of anodic character. The inhibitor was more active in HCI than in H2SO4. The maximum inhibition efficiency approached at 1000 ppm in both the acid medium. The inhibitor was found to adsorb on the mild steel surface according to the Langmuir adsorption isotherm. The surface morphology of mild steel in the presence and absence of inhibitor was studied by using scanning electron microscopic （SEM） images.

Surface modification of magnesium hydroxide by γ-aminopropyltriethoxysilane

Magnesium hydroxide(MH),which is commonly used as a halogen-free flame retardant filler in composite materials,was modified by silanization reaction with γ-aminopropyltriethoxysilane (γ-APS) in aqueous solution at different pH values (pH range from 8.0 to 12.0). The surface properties of grafted γ-APS on MH surface as a function of solution pH value were studied using elemental analysis,Fourier transform infrared spectroscopy and zeta potential measurement. The results show that hydrolysis and condensation of γ-APS are activated in alkaline solution and lead to multilayer adsorption of γ-APS molecules on the surface of MH. The type of adsorption orientation of γ-APS on MH surface is a function of coverage density that is altered by changing solution pH value. At low coverage density (e.g. 55 nm-2),γ-APS molecules are preferentially adsorbed to the surface with the silicon moiety towards the surface,and increasing coverage density (e.g. 90 nm-2) leads to parallel orientation. At an even higher coverage density (e.g. 115 nm-2),γ-APS molecules bond to the surface with the amino moiety towards the surface.

New Synthesized （3-（3,4-dimethoxyphenyl）isoxazole-5- yl） Methanol as Corrosion Inhibitor on Steel in 1 M HCI

The inhibition of corrosion of steel in molar hydrochloric acid solution by new synthesized DMI （（3-（3,4-dimethoxyphenyl）isoxazole-5-yl） methanol） compound is studied by weight loss and electrochemical polarization measurements. The two methods give consistent results. The polarization curves indicate that the DMI compound acts as mixed-type inhibitor. This compound is efficient inhibitor. The inhibition efficiency increases with the increase of inhibitor concentration to reach 96% at 10-3 M for DMI. The temperature effect on the corrosion behavior of steel in 1 M HCI with and without the DMI compound at 10-3 M is studied in the temperature range from 298 to 318 K. The adsorption of inhibitor on the steel surface is found to obey the Frumkin adsorption isotherm model. From the adsorption isotherm, some thermodynamic data for the adsorption process （f, K and △Gads） are calculated and discussed.

Effect of 3-aminotriazole on the corrosion of copper in polluted and unpolluted media

The inhibition of copper corrosion in unpolluted or polluted 3.5% NaCl solution in the absence and presence of 3-amino-1, 2, 4-triazole （ATA） as a corrosion inhibitor was studied by using different electrochemical techniques. Aminotriazole （ATA） is well known as corrosion inhibitor for corrosion of copper and aluminum in unpolluted salt water. The influence of 3-aminotriazole （ATA） on the corrosion behavior of copper in unpolluted and polluted environment has been studied using potentiodynamie and potentiostatic polarization methods. Surface morphological examinations such as SEM, EDS and XPS have also been carried out to understand the mechanism of inhibition of corrosion. Electrochemical measurements and morphological results are clearly show that the inhibitor is strongly adsorbed on the copper surface and form a protective film on the copper surface.

Ethanol Extract of Vitex Doniana as a Green Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Medium

Corrosion is a costly and complicated problem facing mild of Vitex doniana as a corrosion inhibitor for mild steel in HCI medium steel utility. This study investigated the use of ethanol extract Experimental methods used are gravimetric and thermometric The results showed that corrosion rate decreased as the concentration of ethanol extract of Vitex doniana increased and with decrease in temperature. Vitex doniana extract obeyed Langmuir and Tempkin adsorption isotherm. Physical adsorption was proposed from △G° and Ea. Inhibition efficiency （1%） and the degree of surface coverage （0） were calculated and all indicated that Vitex doniana was a good corrosion inhibitor.

Exopolysaccharides from Lactic acid Bacteria as Corrosion Inhibitors

Bacterial EPSs （exopolysaccharides） are believed to play an important role in the environment by promoting survival strategies such as bacterial attachment to surfaces and nutrient trapping, which facilitate processes of biofilm formation and development. These microbial biofilms have been implicated in corrosion of metals, bacterial attachment to prosthetic devices, fouling of heat exchange surfaces, toxicant immobilization, and fouling of ship hulls. In this paper, data on EPS production and the effect of EPS on corrosion of steel produced by Lactobacillus fermentum Ts are presented and discussed. The Lactobacillus fermentum Ts strain was isolated from types of Bulgarian rye flour. It was tested for its ability to produce exopolysaccharides when cultivated in a media containing 10% sucrose, 10% fructose and 10% maltose. The study of the corrosive stability of steel samples was conducted on the gravimetrique method. The rate of corrosion, the degree of protection, and coefficient of protection have been calculated. The structure of layer over steel plates was analysed by SEM （scanning electron microscopy） JSM 5510. It could be underlined that 10% sucrose and 10% maltose in the media stimulated the process of protection of corrosion.

N-methyl-2-(2-nitrobenzylidene) hydrazine carbothioamide——A new corrosion inhibitor for mild steel in 1 mol·L^(-1)hydrochloric acid

The corrosion inhibition of mild steel in 1 mol·L^(-1) hydrochloric acid by N-methyl-2-(2-nitrobenzylidene)hydrazine carbothioamide(MNBHC) was studied using weight loss and electrochemical studies.Results obtained indicate that the inhibitor is effective in hydrochloric acid medium and the efficiency decreases with increase in temperature.Added halide additives improve the efficiency of the inhibitor.The AC impedance studies reveal that the process of inhibition is through charge transfer.Polarization studies indicate the mixed nature of the inhibitor.From the thermodynamic,spectral and surface analyses the nature of adsorption has been found out.The adsorption of the inhibitor on mild steel follows the Langmuir isotherm.

新书推荐

《精细有机化工中间体全书》,《精选实用化工产品300例-原料、配方、工艺及设备》.