Kinetics analysis of the decay of phenylhydrazonopropanedinitrile addition products with thiols in aqueous solutions

1989 ◽  
Vol 54 (12) ◽  
pp. 3387-3396 ◽  
Author(s):  
Marián Antalík ◽  
Ernest Šturdík ◽  
Dušan Podhradský ◽  
Ingrid Poleková ◽  
Ľudovít Drobnica
Keyword(s):  
Experimental Data ◽  
Carbon Atom ◽  
Aqueous Solutions ◽  
Decisive Role ◽  
Kinetic Description ◽  
Kinetics Analysis ◽  
Imino Group ◽  
Ph Values ◽  
Ph Dependent ◽  
Good Agreement

The reactions of phenylhydrazonopropanedinitriles with thiols are reversible and with increasing pH-values of aqueous solutions the equilibrium is shifted them to the side of the reactants. A mechanism of the decay of corresponding addition products was proposed and the kinetic description based on this mechanism is in good agreement with the obtained experimental data. From the viewpoint of the decay, the pH-dependent dissociation of the proton of the imino group formed by addition of thiol to the nitrile carbon atom plays a decisive role. The obtained knowledge is useful with respect to the use of phenylhydrazonopropanedinitriles as affinants for selective and reversible sorption of low-molecular thiols and thiol-proteins in affinity chromatography as well as for the study of the mechanism of the effect of these substances in oxidative and photosynthetic phosphorylation and biological systems in general.

scholarly journals Measurement and Prediction of Densities of Ternary Aqueous Mixtures Involving Sodium Polyacrylate

2004 ◽  
Vol 4 (1) ◽  
pp. 64
Author(s):  
Z. A. Noor Fadzlina ◽  
T. T. Teng ◽  
M. Abdul Rahman
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Percentage Error ◽  
Sodium Polyacrylate ◽  
Aqueous Systems ◽  
Aqueous Mixtures ◽  
Density Prediction ◽  
Density Values ◽  
Good Agreement

The densities of the binary aqueous solutions of sodium polyacrylate (NaPM) at 20°C, 25°C, and 300C up to 0.17 m and LiCI at 25°C and 300C up to 3.13 m were measured using a vibrating tube digital densitimeter. The measured experimental data were then fitted to the polynomial d = do + IA;m'. The densities of the ternary aqueous systems NaPM-NaCI, NaPM-LiCI, and NaPM-sucrose were also =1 measured from 20°C to 30°C. The isopycnotic equation, Imi / moi was used to predict the densities of the ternary aqueous systems mentioned. The results show that predicted and observed density values are in good agreement. The overall percentage error of density prediction for the system NaPM-NaCI-H20 is 0.067. For the system NaPM-LiCI-HP,the overall percentage error is 0.074; and, for the system NaPM-sucrose-H20, the overall percentage error is 0.065.

Ligand Redistribution Equilibria in Aqueous Fluoroberyllate Solutions

1998 ◽  
Vol 53 (11) ◽  
pp. 1294-1300 ◽  
Author(s):  
Michael Schmidt ◽  
Hubert Schmidbaur
Keyword(s):  
Experimental Data ◽  
Ligand Exchange ◽  
Room Temperature ◽  
Chemical Shifts ◽  
Equilibrium Constants ◽  
Individual Species ◽  
Ph Values ◽  
Exchange Processes ◽  
The Individual ◽  
Good Agreement

The composition of aqueous fluoroberyllate solutions has been studied by 9Be and 19F NMR spectroscopy for various ratios of the beryllium and fluorine concentrations, and at different pH values. The equilibrium constants have been determined for the ligand exchange processes, which involve the species [Be(OH2)4]2+, [BeF(OH2)3]+, [BeF2(OH2)2], [BeF3(OH2)]- , and [BeF4]2-. These equilibria are shifted towards [BeF4]2- at high pH. No polynuclear fluoroberyllates have been detected. The fluoride exchange between the individual species is slow on the NMR time scale at room temperature, and separate sharp signals with the expected multiplicity are therefore recorded. Calculated 9Be chemical shifts are in good agreement with experimental data.

scholarly journals Adsorption of Triclocarban on Pristine and Irradiated MWCNTs in Aqueous Solutions

2019 ◽  
Vol 70 (8) ◽  
pp. 2835-2842 ◽  
Author(s):  
Ion Ion ◽  
Raluca Madalina Senin ◽  
Georgeta Ramona Ivan ◽  
Sanda Maria Doncea ◽  
Michael Patrick Henning ◽  
...  
Keyword(s):  
Experimental Data ◽  
Organic Matter ◽  
Humic Acid ◽  
Aqueous Solutions ◽  
Natural Organic Matter ◽  
Environmental Conditions ◽  
Sorption Process ◽  
Ph Values ◽  
Different Temperatures ◽  
The Impact

The adsorption of triclocarban was investigated on pristine and irradiated MWCNTs, at different temperatures, in aqueous synthetic samples at different pH values and for different concentrations of humic acid (HA) from natural organic matter. Commonly used models of the adsorption isotherms, Freundlich and Langmuir were selected to fit the experimental data. The effects of TCC concentration, of the temperature and of the concentration of humic acid from natural organic matter were tested to study the impact of the environmental conditions over the sorption process.

Effects of Inorganic Orthophosphate and Pyrophosphate on Dissolution of Calcium Fluoride in Water

1988 ◽  
Vol 67 (2) ◽  
pp. 447-449 ◽  
Author(s):  
F. Lagerlöf ◽  
E. Saxegaard ◽  
P. Barkvoll ◽  
G. Rølla
Keyword(s):  
Aqueous Solutions ◽  
Calcium Fluoride ◽  
Clinical Studies ◽  
Slow Release ◽  
Dental Enamel ◽  
Fluoride Release ◽  
Ph Values ◽  
Rate Of Dissolution ◽  
Low Concentrations ◽  
Ph Dependent

Calcium and fluoride release from excess solid calcium fluoride was monitored for 15-30 min in aqueous solutions containing various concentrations of inorganic orthophosphate and pyrophosphate. Low concentrations of these ions (1-10 μmol/L) considerably inhibited the rate of dissolution of calcium fluoride. This inhibition was pH-dependent, being reduced at pH values below 5. It is suggested that a reduced calcium fluoride dissolution rate, in the presence of phosphate, can account for the relatively slow loss of calcium fluoride from dental enamel observed in recent clinical studies. It also appears that calcium fluoride coated with phosphate may provide a pH-controlled slow release of fluoride that may be of clinical significance and a major component of the cariostatic mechanism of topically applied fluoride.

Conductimetric studies on aqueous solutions of electrolytes. I. Conductivities of copper sulphate

1983 ◽  
Vol 61 (2) ◽  
pp. 267-268 ◽  
Author(s):  
Victor Hugo Acevedo ◽  
Juana Albarracín De Morán ◽  
Leopoldo Armando Sales
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Copper Sulphate ◽  
Maximum Concentration ◽  
Temperature Range ◽  
Ph Values ◽  
Solutions Of Electrolytes

The specific conductivities and pH values of copper sulphate solutions in water were measured in the temperature range from 10 °C to 50 °C. The data, previously corrected by hydrolysis, were analyzed by means of the Lee Wheaton theory.This fit, for the evaluation of Λ0, R, and KA parameters, is quite satisfactory up to a maximum concentration of 25 × 10−4 moldm−3 and the agreement between experimental data and the literature value for 25 °C is acceptable.

A computational comparison of the speciation of uranyl D-gluconate and uranyl α-isosaccharinate complexes in aqueous solutions.

2012 ◽  
Vol 1475 ◽  
Author(s):  
Krishna Hassomal Birjkumar ◽  
Nikolas Kaltsoyannis
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Aqueous Solutions ◽  
Equatorial Plane ◽  
Density Functional ◽  
Spectroscopic Properties ◽  
Functional Theory ◽  
Coordination Modes ◽  
Ph Dependent ◽  
Computational Comparison

ABSTRACTThe geometries, relative energies and spectroscopic properties of α-isosaccharinate and D-gluconate complexes of uranyl(VI) are studied computationally using density functional theory. The effect of pH is accommodated by varying the number of water and hydroxide ligands accompanying gluconate in the equatorial plane of the uranyl unit. Their relative energies are found to be pH dependent, although the energetic differences between them are not sufficient to exclude the possibility of multiple speciation. The calculated uranyl stretching frequency decreases as pH increases, in agreement with previous experimental data. Three different coordination modes are studied.

Energy Levels and Electromagnetic Transition of 90-94mo Nuclei Using Ibm-1

2020 ◽  
pp. 149-152
Keyword(s):  
Experimental Data ◽  
Transition Probability ◽  
Energy Levels ◽  
Dynamical Symmetry ◽  
Interacting Boson Model ◽  
Excitation Energies ◽  
Electromagnetic Transition ◽  
Boson Model ◽  
Energy States ◽  
Good Agreement

The energy states for the J , b , ɤ bands and electromagnetic transitions B (E2) values for even – even molybdenum 90 – 94 Mo nuclei are calculated in the present work of "the interacting boson model (IBM-1)" . The parameters of the equation of IBM-1 Hamiltonian are determined which yield the best excellent suit the experimental energy states . The positive parity of energy states are obtained by using IBS1. for program for even 90 – 94 Mo isotopes with bosons number 5 , 4 and 5 respectively. The" reduced transition probability B(E2)" of these neuclei are calculated and compared with the experimental data . The ratio of the excitation energies of the 41+ to 21+ states ( R4/2) are also calculated . The calculated and experimental (R4/2) values showed that the 90 – 94 Mo nuclei have the vibrational dynamical symmetry U(5). Good agreement was found from comparison between the calculated energy states and electric quadruple probabilities B(E2) transition of the 90–94Mo isotopes with the experimental data .

Predicting the Effect of Tire Tread Pattern Design on Thick Film Wet Traction

1977 ◽  
Vol 5 (1) ◽  
pp. 6-28 ◽  
Author(s):  
A. L. Browne
Keyword(s):  
Experimental Data ◽  
Network Design ◽  
Thick Film ◽  
Digital Computer ◽  
Analytical Tool ◽  
Design Practice ◽  
Pattern Design ◽  
Performance Results ◽  
Good Agreement

Abstract An analytical tool is presented for the prediction of the effects of changes in tread pattern design on thick film wet traction performance. Results are reported for studies in which the analysis, implemented on a digital computer, was used to determine the effect of different tread geometry features, among these being the number, width, and lateral spacing of longitudinal grooves and the angle of zigzags in longitudinal grooves, on thick film wet traction. These results are shown to be in good agreement with experimental data appearing in the literature and are used to formulate guidelines for tread groove network design practice.

A New Condition of Formation and Stablity of All Crystalline Systems in a Good Agreement with Experimental Data

2015 ◽  
Vol 11 (3) ◽  
pp. 3224-3228
Author(s):  
Tarek El-Ashram
Keyword(s):  
Experimental Data ◽  
Brillouin Zone ◽  
Electron Concentration ◽  
Free Electron ◽  
Lattice Point ◽  
Valence Electron ◽  
Fermi Gas ◽  
Valence Electron Concentration ◽  
Fermi Sphere ◽  
Good Agreement

In this paper we derived a new condition of formation and stability of all crystalline systems and we checked its validity andit is found to be in a good agreement with experimental data. This condition is derived directly from the quantum conditionson the free electron Fermi gas inside the crystal. The new condition relates both the volume of Fermi sphere VF andvolume of Brillouin zone VB by the valence electron concentration VEC as ;𝑽𝑭𝑽𝑩= 𝒏𝑽𝑬𝑪𝟐for all crystalline systems (wheren is the number of atoms per lattice point).

Virus Removal by Filtration

1982 ◽  
Vol 14 (4-5) ◽  
pp. 253-256
Author(s):  
N Sriramula ◽  
M Chaudhuri
Keyword(s):  
Experimental Data ◽  
Escherichia Coli ◽  
Cationic Polyelectrolyte ◽  
Electrokinetic Phenomena ◽  
Virus Removal ◽  
Bacterial Virus ◽  
Gravity Settling ◽  
And Diffusion ◽  
Model Virus ◽  
Good Agreement

An investigation was undertaken on the removal of a model virus, bacterial virus MS2 against Escherichia coli, by sand filtration using untreated, and alum or cationic polyelectrolyte treated media, and uncoagulated as well as alum coagulated influent. Data on discrete virus removal were satisfactorily accounted for by electrokinetic phenomena and diffusion. For virus in association with turbidity, filter coefficients computed from experimental data were in good agreement with those predicted by mechanical straining and gravity settling which were the dominant mechanisms for removal of the turbidity particles to which the viruses attached.

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