scholarly journals Reduction of dicarbonyl compounds on a mercury electrode. II. Reduction mechanism of acetylbenzoyl

1985 ◽  
Vol 63 (4) ◽  
pp. 891-895 ◽  
Author(s):  
J. M. Rodriguez-Mellado ◽  
J. L. Avila ◽  
J. J. Ruiz
Keyword(s):  
Experimental Data ◽  
Reaction Mechanism ◽  
Aqueous Solutions ◽  
Mercury Electrode ◽  
Reduction Mechanism ◽  
Tafel Slopes ◽  
Reaction Orders ◽  
Drop Time ◽  
Ph Range ◽  
Adsorption Phenomena

A study on the electrochemical reduction of acetylbenzoyl on a mercury electrode has been carried out in the pH range 0–9 in buffered aqueous solutions. The effect of pH, drop time, temperature, and acetylbenzoyl concentration on polarographic and kinetic parameters has been studied. The occurrence of adsorption phenomena is inferred from the recordings of C–E curves. Tafel slopes and reaction orders have been obtained at potentials corresponding to the foot of the wave. On the basis of these experimental data, a reaction mechanism is proposed for the zone of potentials where Tafel's law is satisfied.

Polarographic and Cyclic Voltammetric Behaviour of Some Azo Compounds Derived from Sulfonamide in DMF-Aqueous Solutions

1992 ◽  
Vol 57 (2) ◽  
pp. 268-275 ◽  
Author(s):  
El-Sayed M. Mabrouk ◽  
Hamada M. Killa ◽  
Abdel Fattah A. Abdel Fattah ◽  
Shalaby A. Yasen
Keyword(s):  
Reaction Mechanism ◽  
Aqueous Solutions ◽  
Kinetic Parameters ◽  
Alkaline Solution ◽  
Electrode Reaction ◽  
Azo Compounds ◽  
Cyclic Voltammetric ◽  
Ph Range

The polarographic and cyclic voltammetric behaviour of (2-hydroxyphenylazo)-4-benzenesulfonamide and some of its derivatives have been studied in Britton-Robinson buffer series containing 30 vol.% of DMF. Over the entire pH range (2-12), the reduction pathway occurs through an irreversible 4-electron step corresponding to the reduction of N=N center to the amine stage. The voltammograms recorded in acidic and alkaline solution at different scan rates exhibit one or two cathodic peaks depending on the substituent and the pH of the medium. The electrode reaction mechanism was suggested, also the kinetic parameters were calculated.

Adsorption of some Weak Organic Electrolytes from Aqueous Solutions on Silica

2007 ◽  
Vol 555 ◽  
pp. 195-200 ◽  
Author(s):  
S.K. Milonjić ◽  
L.K. Zhigunova ◽  
V.Lj. Pavasović
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Adsorption Isotherms ◽  
Water Purification ◽  
Maximum Amount ◽  
Substituted Phenols ◽  
Batch Method ◽  
Organic Electrolytes ◽  
Method Effects ◽  
Ph Range

The adsorption of organic electrolytes from aqueous solutions on various adsorbents has been frequently investigated because of its importance in water purification. Phenol and substituted phenols are very common contaminants of water. In this paper, the adsorption results of some weak organic electrolytes (hydrochinon, phloroglucin and acidum gallicum) from aqueous solutions on silica are presented. The adsorption of the organics was investigated by the batch method. Effects of solution pHs (in the 2-10 range) and concentrations of these compounds on the adsorption were investigated. In the case of acidum gallicum, adsorption isotherms (in the 2-6 pH range) were determined. The obtained results indicate that the amount of adsorbed acidum gallicum increases with its increasing concentration. The maximum adsorption was recorded at pH=2-3 (pH equal to pHpzc of SiO2) with acidum gallicum molecule being undissociated (pKa= 4.41). The experimental data were fitted with different adsorption isotherms models. The maximum amount of acidum gallicum adsorbed as well as the Freundlich constants of adsorption were calculated. The adsorption of hydrochinon and phloroglucin from aqueous solutions (in the investigated pH range) on silica was negligible.

The Electroreduction of Periodate Anion in Alkaline Media

1971 ◽  
Vol 49 (16) ◽  
pp. 2657-2663 ◽  
Author(s):  
W. R. Fawcett ◽  
Y. C. Kuo Lee
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Double Layer ◽  
Mercury Electrode ◽  
Electrode Reaction ◽  
Alkaline Media ◽  
Dropping Mercury Electrode ◽  
Ph Range ◽  
Theoretical Developments

The electroreduction of periodate anion was studied at a dropping mercury electrode in aqueous solutions in the pH range 11–13.3 where the process is markedly affected by the double layer. The electrode reaction was found to be complex, its mechanism depending on both pH and ionic strength. The effects of the double layer on the component reactions are discussed with respect to current theoretical developments.

scholarly journals Critical Admission Temperature of H2 and CH4 in Nanopores of Exchanged ERI Zeolites

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 160 ◽  
Author(s):  
Karla Quiroz-Estrada ◽  
Miguel Hernández ◽  
Carlos Felipe-Mendoza ◽  
Juana Santamaría-Juárez ◽  
Vitalii Petranovskii ◽  
...  
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Langmuir Equation ◽  
H2 Adsorption ◽  
Heats Of Adsorption ◽  
Low Levels ◽  
Adsorption Phenomena ◽  
Zeolitic Materials

Due to the nanoporous nature of zeolitic materials, they can be used as gas adsorbents. This paper describes the effect of critical admission temperature through narrow pores of natural ERI zeolites at low levels of coverage. This phenomenon occurs by adsorption of CH4 and H2 on pores in natural erionite. The zeolite was exchanged with aqueous solutions of Na+, Mg2+, and Ca2+ salts at different concentrations, times, and temperatures of treatment. Experimental data of CH4 and H2 adsorption were treated by the Langmuir equation. Complementarily, the degree of interaction of these gases with these zeolites was evaluated by the evolution of isosteric heats of adsorption. The Ca2+ and Mg2+ cations favor the adsorption phenomena of H2 and CH4. These cations occupy sites in strategic positions Ca1, Ca2, and Ca3, which are located in the nanocavities of erionite zeolites and K2 in the center of 8MR. Following the conditions of temperature and the exchange treatment, ERICa2 and ERINa3 samples showed the best behavior for CH4 and H2 adsorption.

Reduction and tensammetric pulse-polarographic currents of polynucleotides

1987 ◽  
Vol 52 (11) ◽  
pp. 2810-2818 ◽  
Author(s):  
Emil Paleček ◽  
František Jelen ◽  
Vladimír Vetterl
Keyword(s):  
Diagnostic Criteria ◽  
Pulse Width ◽  
Mercury Electrode ◽  
Pulse Amplitude ◽  
Single Strand ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Adenylic Acid ◽  
Drop Time

The behaviour of electrochemically reducible single-strand polynucleotides (poly(adenylic acid)) and poly(cytidylic acid)) was studied by the differential (derivative) pulse polarography (DPP) and by other methods. Measurements were performed with the help of the dropping mercury electrode under various conditions specified by the pulse width, pulse amplitude, drop time etc. For the faradaic and tensammetric DPP peaks the diagnostic criteria were proposed which make it possible to classify even very small DPP peaks of double helical polynucleotides.

Some Aspects of the Electroreduction of Niazid to Nicotinamide on Mercury Electrodes in Acidic Media

1992 ◽  
Vol 57 (9) ◽  
pp. 1836-1842 ◽  
Author(s):  
Rafael Marín Galvín ◽  
José Miguel Rodríguez Mellado
Keyword(s):  
Electron Transfer ◽  
Essential Role ◽  
Uv Spectroscopy ◽  
Acidic Media ◽  
Polarographic Wave ◽  
Rate Determining Step ◽  
Tafel Slopes ◽  
Reaction Orders ◽  
Mercury Electrodes ◽  
The Waves

The electroreduction of niazid on mercury electrodes has been studied in acidic media (pH < 6). Tafel slopes and reaction orders were obtained at potentials corresponding to the foot of the first polarographic wave. On the basis of both polarographic and voltammetric results it has been shown that the waves appearing at more negative potentials correspond to the reduction of nicotinamide. Protonation of niazid plays an essential role in its reduction and pK values of 1.4, 3.2 and 11.5 were obtained by UV spectroscopy. The process corresponding to the first wave is irreversible, being the second one-electron transfer the rate determining step. Above pH 4 the process is complex due to the overlapping of the waves caused by the occurrence of protonation reactions.

scholarly journals Experimental data on the removal of acid orange 10 dye from aqueous solutions using TiO2/Na-Y zeolite and BiVO4/Na-Y zeolite nanostructures: A comparison study

Data in Brief ◽  
2021 ◽  
Vol 35 ◽  
pp. 106869
Author(s):  
Behzad Rahimi ◽  
Nayereh Rezaie-Rahimi ◽  
Negar Jafari ◽  
Ali Abdolahnejad ◽  
Afshin Ebrahimi
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Comparison Study ◽  
Y Zeolite ◽  
Acid Orange ◽  
Acid Orange 10
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