scholarly journals The application of hydrogen-palladium electrode for potentiometric acid-base determinations in tetrahydrofuran

2013 ◽  
Vol 78 (8) ◽  
pp. 1203-1212
Author(s):  
Anja Jokic ◽  
Radmila Dzudovic ◽  
Ljiljana Jaksic ◽  
Snezana Nikolic-Mandic
Keyword(s):  
Maleic Acid ◽  
Glass Electrode ◽  
Indicator Electrode ◽  
Electrode Pair ◽  
Acid Base ◽  
Palladium Electrode ◽  
The Individual ◽  
Acidity Scale ◽  
Relative Acidity

The application of the hydrogen-palladium electrode (H2/Pd) as the indicator electrode for the determination of relative acidity scale (Es, mV) of tetrahydrofuran (THF) and the potentiometric titrations of acids in this solvent was investigated. The relative acidity scale tetrahydrofuran was determined from the difference half-neutralization potentials of perchloric acid and tetrabutylammonium hydroxide (TBAH), which were measured by using both H2/Pd-SCE and glass-SCE electrode pairs. The experimentally obtained value of Es scale THF with a H2/Pd-SCE electrode pair was 1155 mV, and those obtained with glass-SCE electrode pair 880 mV. By using a H2/Pd indicator electrode, the individual acids (benzoic acid, palmitic acid, maleic acid, acetyl acetone, ?-naphthol) and two component acid mixtures (benzoic acid + ?-naphthol, palmitic acid + ?-naphthol, maleic acid + ?-naphthol and maleic acid + ftalic acid) were titrated with a standard solution of TBAH. In addition, sodium methylate and potassium hydroxide proved to be very suitable titrating agents for titrating of the individual acids and the acids in mixtures, respectively. The relative error of the determination of acids in mixture was less than 3%. The results are in agreement with those obtained by a conventional glass electrode. The advantages of H2/Pd electrode over a glass electrode in potentiometric acid-base determinations in tetrahydrofuran lie in the following: this electrode gives wider relative acidity scale THF, higher the potential jumps at the titration end-point and relatively fast response time; furthermore, it is very durable, simple to prepare and can be used in the titrations of small volumes.

scholarly journals Determination of relative acidity scales for some dipolar aprotic solvents by coulometry using a hydrogen-palladium electrode

2008 ◽  
Vol 73 (8-9) ◽  
pp. 871-878 ◽  
Author(s):  
Radmila Dzudovic ◽  
Ljiljana Jaksic
Keyword(s):  
Perchloric Acid ◽  
Supporting Electrolyte ◽  
Sodium Perchlorate ◽  
Electrode Pair ◽  
Tetrabutylammonium Perchlorate ◽  
Palladium Electrode ◽  
The Difference ◽  
Acidity Scale ◽  
Relative Acidity

A coulometric-potentiometric procedure for the determination of relative acidity scales of acetone, methylethyl ketone, methyl-isobutyl ketone and propylene carbonate is described. The range of the relative acidity scale of a solvent was determined from the difference between the half-neutralization potential of perchloric acid and that of tetrabutylammonium hydroxide. The perchloric acid was generated in situ from a hydrogen-palladium electrode in presence of sodium perchlorate or tetrabutylammonium perchlorate as the supporting electrolyte. The electrode pairs glass-SCE and (H2/Pd)ind-SCE were applied for the measurement of the half-neutralization potentials of the acid and base. A wider range of relative acidity scale of the solvents was obtained with the glass-SCE electrode pair and tetrabutylammonium perchlorate as the supporting electrolyte.

scholarly journals Coulometric-potentiometric determination of autoprotolysis constant and relative acidity scale of water

2010 ◽  
Vol 75 (11) ◽  
pp. 1575-1582 ◽  
Author(s):  
Radmila Dzudovic ◽  
Ljiljana Jaksic
Keyword(s):  
Supporting Electrolyte ◽  
Sodium Perchlorate ◽  
Electrolytic Cell ◽  
Electrode Pair ◽  
Strong Base ◽  
Palladium Electrode ◽  
Oxidation Of Hydrogen ◽  
The Difference ◽  
Acidity Scale ◽  
Relative Acidity

The autoprotolysis constant and relative acidity scale of water were determined by applying the coulometric-potentiometric method and a hydrogen/palladium (H2/Pd) generator anode. In the described procedure for the evaluation of autoprotolysis constant, a strong base generated coulometrically at the platinum cathode in situ in the electrolytic cell, in presence of sodium perchlorate as the supporting electrolyte, is titrated with hydrogen ions obtained by the anodic oxidation of hydrogen dissolved in palladium electrode. The titration was carried out with a glass-SCE electrode pair at 25.0?0.1?C. The value obtained pKw = 13.91 ? 0.06 is in agreement with literature data. The range of acidity scale of water is determined from the difference between the halfneutralization potentials of electrogenerated perchloric acid and that of sodium hydroxide in a sodium perchlorate medium. The halfneutralization potentials were measured using both a glass-SCE and a (H2/Pd)ind-SCE electrode pairs. A wider range of relative acidity scale of water was obtained with the glass-SCE electrode pair.

scholarly journals The Anomalous Influence of Polyelectrolyte Concentration on the Deposition and Nanostructure of Poly(ethyleneimine)/Poly(acrylic acid) Multilayers

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2141 ◽  
Author(s):  
Martin Müller
Keyword(s):  
Acrylic Acid ◽  
Attenuated Total Reflection ◽  
Silicon Substrates ◽  
Acid Base ◽  
Exponential Relationship ◽  
Individual Adsorption ◽  
The Individual ◽  
Poly Acrylic Acid

The deposition and nanostructure of polyelectrolyte (PEL) multilayers (PEMs) of branched poly(ethyleneimine)/poly(acrylic acid) (PEI/PAA) onto silicon substrates was studied in terms of the dependence of pH and the PEL concentration (cPEL) in the individual adsorption steps z. Both a commercial automatic dipping device and a homebuilt automatic stream coating device (flow cell) were used. Gravimetry, SFM, transmission (TRANS) and in situ attenuated total reflection (ATR) FTIR spectroscopy were used for the quantitative determination of the adsorbed amount, thickness, chemical composition and morphology of deposited PEMs, respectively. Firstly, the combination of pH = 10 for PEI and pH = 4 for PAA, where both PEL were predominantly in the neutral state, resulted in an extraordinarily high PEM deposition, while pH combinations, where one PEL component was charged, resulted in a significantly lower PEM deposition. This was attributed to both PEL conformation effects and acid/base interactions between basic PEI and acidic PAA. Secondly, for that pH combination an exponential relationship between PEM thickness and adsorption step z was found. Thirdly, based on the results of three independent methods, the course of the deposited amount of a PEM-10 (z = 10) versus cPEL in the range 0.001 to 0.015 M at pH = 10/4 was non-monotonous showing a pronounced maximum at cPEL = 0.005 M. Analogously, for cPEL = 0.005 M a maximum of roughness and structure size was found. Fourthly, related to that finding, in situ ATR-FTIR measurements gave evidence for the release of outermost located PEI upon PAA immersion (even step) and of outermost PAA upon PEI immersion (odd step) under formation of PEL complexes in solution. These studies help us to prepare PEL-based films with a defined thickness and morphology for interaction with biofluids in the biomedical and food fields.

Differentiating Nonaqueous Titration of Mixtures Containing Acetaminophen and Salicylamide

1973 ◽  
Vol 56 (3) ◽  
pp. 653-655
Author(s):  
Martin I Blake ◽  
Linda B Shumaker
Keyword(s):  
Dosage Forms ◽  
Electrode System ◽  
Glass Electrode ◽  
Tetrabutylammonium Hydroxide ◽  
Titration Procedure ◽  
The Individual

Abstract A differentiating nonaqueous titration procedure is described for the determination of mixtures of acetaminophen and salicylamide. Tetrabutylammonium hydroxide is the titrant and a Fisher titrimeter equipped with a calomel-glass electrode system is used. The technique is applied to the individual components, synthetic mixtures, and complex dosage forms.

Formation constants for selected organo—metal (Al3+, Fe3+)—phosphate complexes

1985 ◽  
Vol 63 (12) ◽  
pp. 3357-3366 ◽  
Author(s):  
Paul A. Arp ◽  
W. Lense Meyer
Keyword(s):  
Organic Acids ◽  
Aqueous Solutions ◽  
Reference Electrode ◽  
Formation Constants ◽  
Glass Electrode ◽  
Metal Phosphate ◽  
Electrode Pair ◽  
Phosphate Ions

The possible formation of organo–metal–phosphate complexes (O–M–P) in aqueous solutions is examined by potentiometric titration analysis. The complex-forming solutions contain Al3+-ions or Fe3+-ions, organic acids (salicylic, phthalic, oxalic, and citric acids) and phosphate ions. The titrations are done within the precipitation-free pH-region from 2 to 4.5 (approximately) at 25 °C under nitrogen at an ionic strength of 0.2 M KCl. The calibration of the electrode pair (glass-electrode, calomel-reference electrode) and the determination of the formation constants are facilitated by analyzing the pertinent curves with the ACBA-(Arena etal.) and MINIQUAD-(Gans etal.) computer programs. The results suggest (i) that O–M–P complexes are readily formed, and that the power of selected organic acids to form ternary mixed-ligand complexes with Al3+-ions and phosphate ions decreases in the order salycilate > citrate > oxalate > phthalate. Also, Fe3+-ions are found to be more strongly bound by salicylate and phosphate ions than Al3+-ions. The effect of O–M–P formation on the chemical speciation of Al in buffered aqueous solutions containing mineral nutrients for the growth of biological organisms is demonstrated for a special case study.

scholarly journals NEW ACID-BASIC INDICATORS: RESEARCH USING A SMARTPHONE

2021 ◽  
Vol 26 (1(77)) ◽  
pp. 97-106
Author(s):  
A. P. Avdeenko ◽  
Yu. P. Holmovoj ◽  
S. A. Konovalova ◽  
I. Yu. Yakymenko
Keyword(s):  
Computer Software ◽  
Glass Electrode ◽  
Acid Base ◽  
Color Transition ◽  
Color Characteristics ◽  
Wide Range ◽  
Acid Base Titration ◽  
Ph Range ◽  
Rgb Model

Modern cameras, desktop scanners, smartphones allow not only registering an image, but also determining its color characteristics. That allows us to quickly, objectively and automatically determine the color characteristics of colored samples in acid-base titration, because there is a significant error at visually determining the pH range of the color transition. In analytical chemistry the characteristics of acid-base indicators are very important, in particular their pH transition interval. But the disadvantage of most indicators is the wide range of color transition: from 1 to 3 pH units. The aim of this work is to find new acid-base indicators that change color in an alkaline environment and have a narrow pH range of the color transition. We have developed the apparatus and technique of convenient and highprecision simultaneous determination of the pH of the medium and the color of the acidbase indicators. In acid-base titration the PH measurements were performed with a combined glass electrode AD1131 by рН-meter AD1000. The color transition was determined with help of a smartphone with the subsequent processing of the results by computer software. The color characteristics were measured for each channel of the RGB model in the range from 0 to 255. Our apparatus is small and mobile, and allows us simultaneously to measure the pH of the medium and accurately to determine the color characteristics. As a result, we can construct graphical dependencies of color on pH for each channel of the RGB model. We found the N-arylsulfonyl-2-aroylamido-1,4-benzo(naphto)quinone monoimines and 2,5-dibenzoylamido-1,4-benzoquinone are good acid-base indicators. They “work” in the pH range from 8.82 to 11.35 and have a very narrow color transition interval from 0.10 to 0.61. Solutions of these compounds in an alkaline medium have bright intense colors due to formation of mesomeric ions. That allows using of these indicators in the titration of weak acids with strong bases and vice versa by the method of neutralization.

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