scholarly journals Corrosion and hydrogen permeation in H2S environments with O2 contamination – Part 3: the impact of acetate-buffered test solution chemistry

CORROSION ◽  
10.5006/3805 ◽  
2021 ◽  
Author(s):  
Gaurav Joshi ◽  
Martien Duvall DEFFO AYAGOU ◽  
Christophe Mendibide ◽  
Thi Tuyet Mai Tran ◽  
BERNARD TRIBOLLET ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Sodium Acetate ◽  
Iron Sulfide ◽  
Electrochemical Impedance ◽  
Hydrogen Permeation ◽  
Solution Chemistry ◽  
Solution Ph ◽  
Acetate Concentration ◽  
X65 Steel ◽  
The Impact

This paper highlights the importance of considering the magnitude of acetate (ethanoate) species concentration on corrosion and hydrogen permeation rates, important factors associated with cracking initiation in steels for sour service qualification. Materials selection relies on standards, such as NACE TM0177 and NACE TM0284, which stipulate that oxygen pollution should be avoided during testing in H2S-containing media. The 5% NaCl test solutions in current standards are buffered using acetic acid (CH3COOH)/sodium acetate (CH3COONa) to fix the solution pH over long periods. In this third paper, as part of a series of articles that evaluate how oxygen entry modifies the corrosion of (and hydrogen permeation across) low alloy steel membranes in H2S-containing solutions, we investigate the effect that changing the solution chemistry has through testing X65 steel in different concentrations of acetic acid and sodium acetate in H2S-saturated 5% NaCl solutions, i.e. Solutions A and B (NACE TM0177-2016), and the HLP solution of NACE TM 0284-2016. Increasing the total acetic acid + acetate concentration encourages a higher average X65 corrosion rate and longer-sustained hydrogen charging flux, assigned to the cathodic reaction rate enhancement by acetic acid and the iron solubilizing effects of acetates. Introducing 300 ppb of dissolved oxygen does not push the solution pH outside of the permitted error range but increases average X65 corrosion rates and, again, helps sustain hydrogen permeation flux for longer. Through an evaluation of the surface structure and electrochemical impedance spectroscopy data, this appears to be down to an increase in the permeability and porosity of the troilite FeStroilite dominant scale. The HLP solution (at pH 3.5), with the highest acetic acid and acetate concentration, is the most aggressive. In this electrolyte, an iron sulfide overlayer structure is attained with an oxygen-rich inner layer between the metal substrate and a thick iron sulfide film.

Palladium(II) Catalyzed Exchange Reactions. XI. Vinyl Propionate Exchange with Acetic Acid Catalyzed by Palladium(II) Acetate

1975 ◽  
Vol 53 (15) ◽  
pp. 2223-2231 ◽  
Author(s):  
Raj N. Pandey ◽  
Patrick M. Henry
Keyword(s):  
Acetic Acid ◽  
Sodium Acetate ◽  
Exchange Reactions ◽  
Free System ◽  
Acetate Concentration ◽  
Rate Expression ◽  
Π Complex ◽  
Acid Catalyzed ◽  
Kinetics Of ◽  
Vinyl Propionate

The kinetics of the palladium(II) acetate catalyzed exchange of vinyl propionate with acetic acid solvent to give vinyl acetate has been studied in the sodium acetate concentration range from 0 to 1 M. The exchange rate first sharply increases as [NaOAc] increases, reaches a maximum at about 0.2 M and then gradually decreases as the sodium acetate concentration is in-creased to 1.0 M. Using previous results on the equilibrium between palladium(II) acetate and sodium acetate in acetic acid it can be shown that the rate expression for exchange is: rate = (ko + kt[Pd3(OAc)6] + kd[Na2Pd2(OAc)6]) [CH2=CHO2CC2H5] where ko = 2 × 10−4 s−1, kt = 0.045 M−1 s−1, and kd = 0.089 M−1 s−1. A monomeric palladium(II) species, Na2Pd(OAc)4, formed at high [NaOAc] is unreactive. Since the rate expression does not contain a term in [NaOAc], the sodium acetate serves only to convert one palladium(II) species to another. The lack of a [NaOAc] term in the rate expression for the Na2Pd2(OAc)6 catalyzed reaction is believed to result from cancellation of an inhibitory term for π-complex formation by a catalytic term in [NaOAc] in the rate determining conversion of π -complex to σ-complex (acetoxypalladation). Stereochemical studies indicate that acetoxypalladation is nonstereospecific. This result is expected since in the chloride free system acetate is both a ligand and a reactant. Thus it can attack from both inside and outside the coordination sphere of Pd(II).

scholarly journals Acetate-Mediated Growth Inhibition in Sterol 14α-Demethylation-Deficient Cells of Candida albicans

1999 ◽  
Vol 43 (1) ◽  
pp. 100-105 ◽  
Author(s):  
Osamu Shimokawa ◽  
Hiroaki Nakayama
Keyword(s):  
Acetic Acid ◽  
Candida Albicans ◽  
Growth Inhibition ◽  
Sodium Acetate ◽  
Culture Medium ◽  
Susceptibility Testing ◽  
Agar Medium ◽  
Acetate Concentration ◽  
The Media ◽  
Layer Chromatography

ABSTRACT Candida albicans is a fungus thought to be viable in the presence of a deficiency in sterol 14α-demethylation. We showed in a strain of this species that the deficiency, caused either by a mutation or by an azole antifungal agent, made the cells susceptible to growth inhibition by acetate included in the culture medium. Studies with a mutant demonstrated that the inhibition was complete at a sodium acetate concentration of 0.24 M (20 g/liter) and was evident even at a pH of 8, the latter result indicating the involvement of acetate ions rather than the undissociated form of acetic acid. In fluconazole-treated cells, sterol profiles determined by thin-layer chromatography revealed that the minimum sterol 14α-demethylation-inhibitory concentrations (MDICs) of the drug, thought to be the most important parameter for clinical purposes, were practically identical in the media with and without 0.24 M acetate and were equivalent to the MIC in the acetate-supplemented medium. The acetate-mediated growth inhibition of azole-treated cells was confirmed with two additional strains of C. albicans and four different agents, suggesting the possibility of generalization. From these results, it was surmised that the acetate-containing medium may find use in azole susceptibility testing, for which there is currently no method capable of measuring MDICs directly for those fungi whose viability is not lost as a result of sterol 14α-demethylation deficiency. Additionally, the acetate-supplemented agar medium was found to be useful in detecting reversions from sterol 14α-demethylation deficiency to proficiency.

Synthesis and Caracterization of some New 1H-3-aryl-7-etoxycarbonyl-6-methyl-pyrazolo[5,1-c][1,2,4]triazoles

2008 ◽  
Vol 59 (1) ◽  
pp. 41-44
Author(s):  
Maria-Daniela Sofei ◽  
Maria Ilici ◽  
Valentin Badea ◽  
Carol Csunderlik ◽  
Vasile-Nicolae Bercean
Keyword(s):  
Mass Spectrometry ◽  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Sodium Acetate ◽  
Glacial Acetic Acid ◽  
Ir And Nmr Spectroscopy

The synthesis of 1H-3-aryl-7-ethoxycarbonyl-6-methyl-pyrazolo[5,1-c][1,2,4]triazoles (2) was carried out by cyclization of 1H-5-arylidenehydrazino-4-ethoxycarbonyl-3-methyl-pyrazoles (1) in the presence of bromine using glacial acetic acid as solvent and sodium acetate as base. The new nine obtained compounds were characterized by IR and NMR spectroscopy and mass spectrometry.

Novel Synthesis of 4-Benzylidene-2-((1-phenyl-3,4-dihydroisoquinoline-2(1H)-yl)methyl) oxazol-5(4H)-one Derivatives Using 1,2,3,Tetrahydroisoquinoline and their Antimicrobial Activity

2020 ◽  
Vol 17 (5) ◽  
pp. 396-403
Author(s):  
Nalla Krishna Rao ◽  
Tentu Nageswara Rao ◽  
Botsa Parvatamma ◽  
Y. Prashanthi ◽  
Ravi Kumar Cheedarala
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Acetic Acid ◽  
Sodium Acetate ◽  
Good Activity ◽  
Activity Profile ◽  
Aryl Aldehydes ◽  
Chemical Structures ◽  
Novel Synthesis ◽  
Target Molecules

Aims: A series of six 4-benzylidene-2-((1-phenyl-3,4-dihydro isoquinoline-2(1H)-yl)methyloxazol- 5(4H)-one derivatives were synthesized by condensation of substituted aryl aldehydes with 2-(2-(1-phenyl-3,4- dihydro isoquinoline-2(1H)-acetamido)acetic acid in the presence of sodium acetate, acetic anhydride and zinc oxide as catalysts. Background: Novel Synthesis of 4-Benzylidene-2-((1-phenyl-3,4-dihy droisoquinoline-2(1H)-yl)methyl)oxazol- 5(4H)-one derivatives using 1,2,3,Tetrahydroisoquinoline and their antimicrobial activity. Objective: The title compounds can be synthesized from 1,2,3,4-tetrahydroisoquinoline. Methods: The target molecules, i.e., 4-benzylidene-2-((1-phenyl-3, 4-dihydro isoquinoline-2(1H)-yl) methyl) oxazol-5(4H)-one derivatives (8a-8f) have been synthesized from 1,2,3,4-tetrahydroisoquinoline which was prepared from benzoic acid in few steps. Results: All the six compounds were evaluated based on advanced spectral data (1H NMR, 13C NMR & LCMS), and the chemical structures of all compounds were determined by elemental analysis. Conclusion: Antibacterial activity of the derivatives was examined for the synthesized compounds and results indicate that compound with bromine substitution has a good activity profile.

EUROPIUM OXALATE ION ASSOCIATION IN WATER

1966 ◽  
Vol 44 (24) ◽  
pp. 3057-3062 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Acetic Acid ◽  
Ionic Strength ◽  
Stability Constant ◽  
Stability Constants ◽  
Aqueous Phase ◽  
Sodium Acetate ◽  
Ion Association ◽  
Sodium Oxalate ◽  
Aqueous Sodium ◽  
Oxalate Ion

The partitioning of radiotracer 152/151Eu between aqueous sodium oxalate (Na2L) solutions and toluene solutions of thenoyltrifluoroacetone (HTTA) has been studied as a function of the oxalate concentration. The pH of the aqueous phase was controlled by means of sodium acetate – acetic acid mixtures and the ionic strength (I) by NaCl or NaClO4.At low ionic strengths (~0.05) and [L] ~10−4 M EuL+ formed, but at I = 0.95 and [L] ~10−3 M EuL2− also formed. Stability constants for the 1:1 and 1:2 (metal:ligand) complexes are reported.The magnitudes of the stepwise stability constant ratios are discussed.

The impact of solution chemistry of electrolyte on the sorption of pentachlorophenol and phenanthrene by natural hematite nanoparticles

2014 ◽  
Vol 466-467 ◽  
pp. 577-585 ◽  
Author(s):  
Fanfeng Zeng ◽  
Yan He ◽  
Zhenghua Lian ◽  
Jianming Xu
Keyword(s):  
Solution Chemistry ◽  
Hematite Nanoparticles ◽  
The Impact

Optimized Production of Xylooligosaccharides from Poplar: A Biorefinery Strategy with Sequential Acetic Acid/Sodium Acetate Hydrolysis Followed by Xylanase Hydrolysis

2021 ◽  
Author(s):  
Hong Liao ◽  
Wenjun Ying ◽  
Xin Li ◽  
Junjun Zhu ◽  
Yong Xu ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Sodium Acetate

scholarly journals A Theoretical and Experimental Study of Electrochemical pH Control at Gold Interdigitated Microband Arrays

2021 ◽  
Author(s):  
Bernardo Patella ◽  
Robert Daly ◽  
Ian Seymour ◽  
Pierre Lovera ◽  
James Rohan ◽  
...  
Keyword(s):  
Electrode Array ◽  
Ph Control ◽  
Reduction Peak ◽  
Solution Ph ◽  
Ph Indicator ◽  
Ph Change ◽  
Initial Ph ◽  
The Impact ◽  
Strong Acids

In electroanalysis, solution pH is a critical parameter that often needs to be adjusted and controlled for the detection of particular analytes. This is most commonly performed by the addition of chemicals, such as strong acids or bases. Electrochemical in-situ pH control offers the possibility for the local adjustment of pH at the point of detection, without additional reagents. FEA simulations have been performed to guide experimental design for both electroanalysis and in-situ control of solution pH. No previous model exists that describes the generation of protons at an interdigitated electrode array in buffered solution with one comb acting as a protonator, and the other as the sensor. In this work, FEA models are developed to provide insight into the optimum conditions necessary for electrochemical pH control. The magnitude of applied galvanostatic current has a direct relation to the flux of protons generated and subsequent change in pH. Increasing the separation between the electrodes increases the time taken for protons to diffuse across the gap. The final pH achieved at both, protonators and sensor electrodes, after 1 second, was shown to be largely uninfluenced by the initial pH of the solution. The impact of buffer concentration was modelled and investigated. In practice, the pH at the electrode surface was probed by means of cyclic voltammetry, i.e., by cycling a gold electrode in solution and identifying the potential of the gold oxide reduction peak. A pH indicator, methyl red, was used to visualise the solution pH change at the electrodes, comparing well with the model’s prediction

scholarly journals Influence of phytohormones on vegetative propagation of different forms of pannonian thyme (Thymus pannonicus All.)

2020 ◽  
Vol 26 (2) ◽  
pp. 39-52
Author(s):  
Vladimir Filipović ◽  
Vladan Ugrenović ◽  
Zoran Maksimović ◽  
Vera Popović ◽  
Danica Paunović ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Root Hairs ◽  
Morphological Properties ◽  
Naphthalene Acetic Acid ◽  
Plant Establishment ◽  
Rooted Cuttings ◽  
Average Percentage ◽  
Plant Collection ◽  
Rooting Of Cuttings ◽  
The Impact

The paper examined the impact of the application of three different phytohormones (INCIT 2, INCIT 5 and INCIT 8, all based on a-Naphthalene Acetic Acid (NAA)), with the cuttings of two forms of Pannonian thyme (the L-16 form, with hairy leaves, and the L-9 form, with hairless leaves), established during two periods (March and May), on the percentage of the rooted cuttings and the morphological properties of the seedlings. As the control, the variant without the application of the phytohormones was taken. The research was conducted in the period from 2019 to 2020, in a plastic greenhouse, using the plant collection of the Institute for Medicinal Plants Research "Dr Josif Pančić", which is located in Pančevo city, Serbia (44°52'20"N; 20°42'06"E; 74 m.a.s.l.). For this research was used the Pannonian thyme species (Thymus pannonicus All.) from the Lamiaceae family, which is grown and produced at the Institute. Plant establishment was carried out in four repetitions with 33 cuttings per each variant. Standard measures of care were used during the period of production of Pannonian thyme. The measurement was performed after 60 days from the date of conducted the experiment. The following parameters were measured: the percentage of rooted cuttings (%), the mass of the rooted plantlings (g), the mass of roots (g), the length of rooting (cm) and the number of root hairs of the formed rootings. The measuring was done using a ruler, millimetre paper and an analytical balance. Given the results achieved, INCIT 2 proved to be the most suitable phytohormone for the rooting of Pannonic thyme cuttings, with the average percentage of rooted cuttings of 61.3%. The lowest rooting percentage was recorded in the control variant, only 29.4%. Satisfactory rooting was found in the cuttings treated with INCIT 8 (57.6%). The L-16 form cuttings showed a higher rooting rate, an average of 53.8%, whereas the L-9 form cuttings had a lower average percentage of rooted cuttings (45.0%) for both plant establishment periods. Greater success and quality in the rooting of cuttings was recorded in the second (May) period of plant establishment, averaging 58.1%, which was higher by 17.4% than the percentage of rooted cuttings in the first establishment period (40.7%). It is important to note that the rooting of the L-9 form was significantly higher in the second establishment period (58.1%) than that in the first establishment period (31.9%).

scholarly journals Processing variables of direct-write, near-field electrospinning impact size and morphology of gelatin fibers

2020 ◽  
Author(s):  
Zachary G. Davis ◽  
Aasim F. Hussain ◽  
Matthew B. Fisher
Keyword(s):  
Acetic Acid ◽  
Acid Concentration ◽  
Near Field ◽  
Fiber Formation ◽  
Direct Write ◽  
Acetic Acid Concentration ◽  
Direct Writing ◽  
Fiber Morphology ◽  
Gelatin Concentration ◽  
The Impact

AbstractSeveral biofabrication methods are being investigated to produce scaffolds that can replicate the structure of the extracellular matrix. Direct-write, near-field electrospinning of polymer solutions and melts is one such method which combines fine fiber formation with computer-guided control. Research with such systems has focused primarily on synthetic polymers. To better understand the behavior of biopolymers used for direct-writing, this project investigated changes in fiber morphology, size, and variability caused by varying gelatin and acetic acid concentration, as well as, process parameters such as needle gauge and height, stage speed, and interfiber spacing. Increasing gelatin concentration at a constant acetic acid concentration improved fiber morphology from large, planar structures to small, linear fibers with a median of 2.3 µm. Further varying the acetic acid concentration at a constant gelatin concentration did not alter fiber morphology and diameter throughout the range tested. Varying needle gauge and height further improved the median fiber diameter to below 2 µm and variability of the first and third quartiles to within +/-1 µm of the median for the optimal solution combination of gelatin and acetic acid concentrations. Additional adjustment of stage speed did not impact the fiber morphology or diameter. Repeatable interfiber spacings down to 250 µm were shown to be capable with the system. In summary, this study illustrates the optimization of processing parameters for direct-writing of gelatin to produce fibers on the scale of collagen fibers. This system is thus capable of replicating the fibrous structure of musculoskeletal tissues with biologically relevant materials which will provide a durable platform for the analysis of single cell-fiber interactions to help better understand the impact scaffold materials and dimensions have on cell behavior.

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