The effect of sodium benzoate and sodium 4-(phenylamino)benzenesulfonate on the corrosion behavior of low carbon steel

Abstract  The effect of sodium benzoate (SB) and sodium 4-(phenylamino)benzenesulfonate (SPABS) on the corrosion behavior of low carbon steel has been investigated using gravimetric method in the temperature range of 30–80 °C, velocity range of 1.44–2.02 m s⁻¹ and concentration range of 6.94 × 10⁻⁴ to 4.16 × 10⁻³ mol dm⁻³ SB and 3.69 × 10⁻⁴ to 2.06 × 10⁻³ mol dm⁻³ SPABS. Optimization of temperature, fluid velocity, and inhibitors concentration has been made. The obtained results indicate that the inhibition efficiency (w _IE %) at 1.56 m s⁻¹ is not in excess of 81.5% at 4.16 × 10⁻³ mol dm⁻³ SB and 84.4% at 2.06 × 10⁻³ mol dm⁻³ SPABS. The inhibitive performance of these compounds showed an improvement with increasing concentration up to critical values of SB and SPABS; beyond these concentrations no further effectiveness is observed. These inhibitors retard the anodic dissolution of low carbon steel by protective layer bonding on the metal surface. The adsorption of SB and SPABS on the low carbon steel surface was found to obey the Freundlich isotherm model. The FT-IR spectroscopy was used to analyze the surface adsorbed film. Graphical abstract  Low carbon steel corrosion in presence of sodium benzoate and sodium 4-(phenylamino)benzenesulfonate has been investigated. The adsorption mechanism obeyed Freundlich isotherm model. FT-IR was used to analyze the adsorbed film      

Photoinduced intramolecular charge transfer of sodium 4-(N,N-dimethylamino) benzenesulfonate

A new dual fluorescent N,N-dimethylaniline derivative, sodium 4-(N,N-dimethylamino)-benzenesulfonate (SDMAS), is reported. In SDMAS, the electron acceptor is linked to the phenyl ring via a sulfur atom at the para-position of the electron donor. It was found that SDMAS emits dual fluorescence only in highly polar solvent water but not in organic solvents such as formamide, methanol and acetonitrile. In organic solvents only a single-band emission at ca.360 nm was observed in the short wavelength region. The dual fluorescence of SDMAS in water was found at 365 and 475 nm, respectively. Introduction of organic solvent such as ethanol, acetonitrile, and 1,4-dioxane into aqueous solution of SDMAS leads to blue-shift and quenching of the long-wavelength emission. Measurements of steady-state and picosecond time-resolved fluorescence indicate that the long wavelength fluorescence is emitted from a charge transfer (CT) state that is populated from the locally excited (LE) state, with the latter giving off the     

Electrochemical behavior and differential pulse voltammetric detection of thiobencarb on 2-(4-((4-ethoxyphenyl)diazenyl)phenylamino)ethanol-modified carbon paste electrode

Cyclic voltammetry, chronoamperometry, and rotating disk electrode voltammetry were used to investigate the electrochemical behavior of thiobencarb (TB) at carbon paste electrode modified with an azo dye, 2-(4-((4-ethoxyphenyl)diazenyl)phenylamino)ethanol (EDPE), EDPE/modified carbon paste electrode (MCPE). The modified electrode showed high electrocatalytic activity toward thiobencarb. The current was enhanced significantly relative to the situation prevailing when a bare glassy carbon electrode was used. The kinetics parameters of this process were calculated, the apparent electron transfer rate constant k _s and α (charge transfer coefficient between electrode and EDPE) were 14.6 s⁻¹ and 0.48, respectively. The experimental parameters were optimized, and the mechanism of the catalytic process was discussed. The best defined cathodic peak was obtained with 0.1 M acetate buffer (pH 3.0). The response of the sensor was very quick, and response time was approximately 5 s. The differential pulse voltammetry response of the MCPE was linear against the concentration of TB in the range of 0.96 to 106 μg L⁻¹. The limit of detection was found to be 0.025 μg L⁻¹. The precision was examined by carrying out eight replicate measurements at a concentration of 25 μg L⁻¹ TB; the relative standard deviation was 2.9%.     

Inhibitor effect of sodium benzoate on the corrosion behavior of nanocrystalline pure iron metal in near-neutral aqueous solutions

Nanocrystalline iron coating was produced on carbon steel surface by pulse electrodeposition using citric acid bath. The grain size of a nanocrystalline surface was analyzed by X-ray diffractometry and scanning electron microscopy. The electrochemical behavior of nanocrystalline iron coating in the presence of sodium benzoate was evaluated in 30 mg l^-1 NaCl + 70 mg l^-1 Na₂SO₄ aqueous solution using potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results were compared with that of the coarse-grained iron surface. The thermodynamic properties of the inhibitor adsorption were also determined. The results indicated that corrosion inhibition of sodium benzoate in near-neutral aqueous solution was increased as the grain size of iron was decreased from micro- to nanocrystalline surface. This was reported in terms of excess free energy of nanocrystalline surface.     

3-(4-氨基苯基偶氮)苯磺酸钠的合成

氨基甲基苯基偶氮苯磺酸钠;3-(4-氨基苯基偶氮)苯磺酸钠的合成     

Characterization and aging of aqueous vesicular dispersions of sodium 4-(1′-heptylnonyl)benzenesulfonate

Vesicles formed by sonication of aqueous dispersions of liquid crystals of the double-tailed surfactant sodium 4-(1′-heptylnonyl)benzenesulfonate (SHBS) are examined with several techniques. The average diameter of the vesicles prepared in water is about 450 Å. The average size decreases when prepared in NaCl or at higher surfactant concentrations. The presence of a few large liquid crystallites in the dispersion, as detected by fast-freeze cold-stage transmission electron microscopy, is shown to severely bias the measurement of vesicle sizes by quasi-elastic light-scattering techniques. The commonly used techniques of gel-permeation chromatography and ultrafiltration are shown to be ineffective in separating liquid crystals from SHBS vesicle dispersions. Vesicle preparation in the presence of uranyl acetate is shown to dramatically reduce the vesicle size. The spontaneous, irreversible reversion of vesicles to liquid crystallites as the dispersions age is documented and proves that SHBS vesicles are not equilibrium structures in water or brine.     

Spectral and thermal studies of 4-(phenyldiazenyl)phenyl 2-furoate as corrosion inhibitor for carbon steel

The azo-ester, namely 4-(phenyldiazenyl)phenyl 2-furoate (PPF) by a coupling reaction between 4-(phenyldiazenyl)phenol and 2-furoyl chloride in the presence of pyridine was obtained. For characterization of this compound UV–Vis, FTIR, and thermal analysis were used. PPF was investigated as corrosion inhibitor for carbon steel in saline waters using potentiodynamic polarization. Morphology of the surface before and after corrosion was examined by optical microscopy. Potentiodynamic polarization shows that the corrosion current densities decrease and values of polarization resistance and inhibition efficiency increase with PPF concentration reaching a maximum of 89.6 %, at 0.1 mmol L^?1.     

Smectic A and smectic C materials: partially deuteriated chiral liquid crystals (S)-(-)-2-methylbuty 4-(4-(d13)-hexyloxyphenyl)benzoate and (S)-(-)-2-methylbutyl 4-(4-(d17)-octyloxyphenyl)benzoate

In order to study the difference in microscopic orientation of ferro- and antiferroelectric liquid crystalline molecules, we synthesized the partially deuteriated chiral compounds, (S)-(^-)-2-methylbutyl 4-(4-(d₁₃)-hexyloxy- and (S)-(^-)-2-methylbutyl 4-(4-(d₁₇)-octyloxy-phenyl)benzoates. Fundamental physical properties such as phase transition temperatures, spontaneous polarization and tilt angle were determined. Polarized FTIR measurements were also made to provide information on molecular structure and orientation.     

Smectic A and smectic C materials: partially deuteriated chiral liquid crystals (S)-(-)-2-methylbuty 4-(4-(d13)-hexyloxyphenyl)benzoate and (S)-(-)-2-methylbutyl 4-(4-(d17)-octyloxyphenyl)benzoate

In order to study the difference in microscopic orientation of ferro- and antiferroelectric liquid crystalline molecules, we synthesized the partially deuteriated chiral compounds, (S)-(^-)-2-methylbutyl 4-(4-(d₁₃)-hexyloxy- and (S)-(^-)-2-methylbutyl 4-(4-(d₁₇)-octyloxy-phenyl)benzoates. Fundamental physical properties such as phase transition temperatures, spontaneous polarization and tilt angle were determined. Polarized FTIR measurements were also made to provide information on molecular structure and orientation.     

Characterization and corrosion behavior of injection molded 17-4 PH steel electrochemically coated with poly[trans-dichloro(4-vinylpyridine)ruthenium]

The present study describes preliminary results on the corrosion resistance of injection molded 17-4 PH stainless steel potentiostatically coated with poly {trans-[RuCl₂(vpy)₄]}, where vpy (4-vinylpyridine) acts as a ligand. The coated electrodes were characterized by scanning electron microscopy and energy dispersive spectroscopy, as well as by electrochemical techniques. The microstructural analysis indicated that the films reached up to 100 μm thickness. Cyclic voltammetry was carried out in 0.1 M tetrabutylammonium hexafluorophosphate/methyl isobutyl ketone. The results revealed a scan rate dependent wave corresponding to a Ru²⁺/Ru³⁺ redox reaction, thus confirming the presence of ruthenium in the films. Anodic polarization tests were performed in 3% NaCl in order to estimate the anodic dissolution current density and the corrosion rate of the material. The results indicated that coating the substrate improved the corrosion resistance of the material. Received: 13 May 1999 / Accepted: 14 October 1999     

Mesogenic properties of cycloalkylmethyl 4-(4'-octoxybiphenyl-4-carbonyloxy)benzoate

Four analogous compounds, cyclohexylmethyl 4-(4'-octoxybiphenyl-4-carbonyloxy)benzoate (2), cyclopentylmethyl 4-(4'-octoxybiphenyl-4-carbonyloxy)benzoate (3), cyclobutylmethyl 4-(4'-octoxylbiphenyl-4-carbonyloxy)benzoate (4) and cyclopropylmethyl 4-(4'-octoxylbiphenyl-4-carbonyloxy)benzoate (5) were prepared. They all exhibit SmA, SmC and SmX phases.     

Synthesis of a silicon-containing flame retardant and its synergistic effect with potassium-4-(phenylsulfonyl)benzenesulfonate (KSS) in polycarbonate (PC)

A novel flame retardant (DAPSiO), containing silicon and nitrogen, was synthesized by using dichlorodiphenylsilane, γ-chloropropyl methyl dimethoxysilane and 1,2-ethanediamine. DAPSiO was used together with potassium-4-(phenylsulfonyl)benzenesulfonate (KSS) to prepare a flame-retardant system for polycarbonate (PC). The structure of DAPSiO was characterized by Fourier transform infrared spectroscopy (FTIR), and ¹H-NMR tests. Flammability and thermal behaviors of PC/KSS/DAPSiO systems were estimated by limited oxygen index (LOI), vertical burning test (UL-94) and thermogravimetric analysis (TGA) tests. The results showed that the flame retardancy and thermal stability of PC/KSS system were improved with the addition of DAPSiO. When 1 wt% DAPSiO and 0.5 wt% KSS were incorporated, the LOI value of PC was found to be 44, and class V-0 of UL-94 test was passed. The scanning electron microscopy (SEM) and FTIR indicated that PC/KSS/DAPSiO system held a more cohesive and denser char structure when compared with pure PC and PC/KSS system.     

The effect of acetic acid on the pit propagation in CO2 corrosion of carbon steel

The role of acetic acid (HAc) on the pit growth in CO₂ corrosion of carbon steel pipelines is studied by means of an artificial pit electrode. The current flowing between the artificial pit and the outer surface was measured with a zero resistance ammeter. It is shown that the corrosion potential increases with increasing HAc concentration. Depletion of HAc inside the pit imposed a potential difference that triggered the pit growth. The pit did not grow in absence of HAc. The pit growth was self-sustained only to a certain pit depth, beyond which the dissolution current at the bottom of the pit vanished. This is in good agreement with field observations mainly in the case of top-of-line corrosion phenomena.     

Synthesis of oligomeric 4-(glycosyloxy)benzoate macrocyclic glycosides

Clemoarmanoside A and Clemahexapetoside A, two novel cyclic dimers of 4-(glycosyloxy)benzoates containing the unusual d-allopyranose as one of the sugar units, were synthesized for the first time. The convenient synthetic approach was adapted to the assembly of the symmetrical trimeric, tetrameric, and pentameric congeners. The synthesis clarified the discrepancy in the NMR data reported for the natural products. X-ray diffraction analysis of Clemahexapetoside A revealed that it adopted an armchair conformation with two carbohydrate rings as the arms and two aromatic rings as the back and seat, respectively.     

Synthesis and Crystal Structure of （3R,4R）-5-（2,4-Dichlorobenzoyl）-4-（4-nitrophenyl）-6-（phenylamino）-3,4-dihydro-2H-thiopyran-3-carbonitrile

The title compound(C25H16Cl2N3O3S),as a thiopyran derivative,has been synthe-sized by the cyclization of an organic intermediate obtained from Baylis-Hillman adducts with a β-aroylthioamide using copper(I) salt as the catalyst.The crystal belongs to the monoclinic system,space group P21/c with a = 13.668(3),b = 8.4803(17) c = 21.999(4) ,β = 113.57(3)°,V = 2337.2(10) 3,Z = 4,Mr = 510.38,Dc = 1.451 g/cm3,μ = 0.401 mm-1,F(000) = 1048,the final R = 0.0487 and wR = 0.1079 for 3678 observed reflections with I > 2σ(I).     

Synthesis and Crystal Structure of (Z)-Ethyl 5-(phenylamino)-3-(phenylimino)-3H-1,2-dithiole-4-carboxylate

The compound (Z)-ethyl 5-(phenylamino)-3-(phenylimino)-3H-1,2-dithiole-4-carboxylate 3 has been synthesized by the reaction of ethylacetoacetate 1 and phenylisothiocyanate 2. Its structure has been established by ¹H NMR, ¹³C NMR, infrared, mass spectra, and x-ray crystallography.      

Cyclodextrin Complexation of the Stilbene 4-(2-(4-Tert-butylphenyl)ethen-1-yl)- benzoate and the Self-assembly of Molecular Devices

E-4-(2-(4- tert - butylphenyl) ethen-1- yl)benzoate, E-1^–, photoisomerizes to the Z-1^– isomer and vice versa in the free state and in the binary complexes 2·E-1^–, 2·Z-1^–, 3·E-1^– and 3·Z-1^– where 2 is the urea-linked cyclodextrin N-(6 ^A -deoxy--cyclodextrin-6 ^A - yl)-N-(6 ^A -deoxy--cyclodextrin-6 ^A - yl)urea and 3 is N,N- bis(6 ^A -deoxy--cyclodextrin-6 ^A - yl)urea. In 2·E-1^–and 3·E-1^– the stilbene occupies both cyclodextrin (CD) components of 2 and 3, whereas in 2·Z-1^– and 3·Z-1^– it only occupies one CD component while the other CD component is unoccupied. 4- tert - Butylphenolate, 4^–, and its carboxylate, 5^–, and sulfonate, 6^–, analogues form the ternary complex 2·Z-1^–·4^– and its analogues and also 3·Z-1^–·4^– and its analogues. These photoisomerize to 2·E-1^–and 3·E-1^– and either free 4^–, 57^– or 6^– and thereby function as molecular devices.