Determination of the activity coefficients in the aliphatic alcohol-non-polar solvent systems

1987 ◽  
Vol 52 (9) ◽  
pp. 2142-2148 ◽  
Author(s):  
Jaromír Hejda ◽  
Věra Jedináková
Keyword(s):  
Aqueous Solutions ◽  
Boric Acid ◽  
Activity Coefficients ◽  
Organic Phase ◽  
Aliphatic Alcohol ◽  
Polar Solvent ◽  
Acid Extraction ◽  
Solvent Systems ◽  
Main Component

A method is proposed for the determination of the activity coefficients in aliphatic alcohols-non-polar solvent systems that are the main component of the organic phase in the boric acid extraction from aqueous solutions.

scholarly journals DETERMINATION OF TYPE OF SOLVATE OF PHOSPHORIC ACID DURING ITS EXTRACTION BY TRIBUTYL PHOSPHATE

2019 ◽  
Vol 62 (5) ◽  
pp. 104-109
Author(s):  
Nikolai F. Kizim ◽  
Anastasiya E. Tarasenkova
Keyword(s):  
Phosphoric Acid ◽  
Aqueous Solutions ◽  
Aqueous Phase ◽  
Equilibrium Constants ◽  
Material Balance ◽  
Mass Action ◽  
Acid Extraction ◽  
Processes And Reactions ◽  
Ionic Equilibria

The extraction of phosphoric acid with a solution of tri-n-butyl phosphate (TBP) in toluene from its individual aqueous solutions in a concentration range of 0-11 M is investigated. The experiments are performed at room temperature (20 ± 1 °С). The isotherms of extraction of phosphoric acid under conditions of equality of the volumes of the saturating aqueous phase and the receiving organic phase are constructed. The extraction isotherm is nonlinear, but to an acid concentration in the aqueous phase of ~ 8 M, it is close to linear, and at higher concentrations, the amount of extracted acid increases harshly. To establish the mechanism of acid extraction in the system phosphoric acid – 0.1 M solution of TBP in toluene the method of combining a laboratory and computational experiment is proposed. The optimal parameters describing the extraction of phosphoric acid from natural aqueous solutions are determined. Calculations performed in two approximations were made. In the first approximation the condition of ideality of systems is accepted. In the second approximation the deviations of the properties of phosphoric acid solutions in aqueous solution are taken into account. For the two approximations the preferential extraction of phosphoric acid molecules in the form of H3PO4 ∙ nTBP type solvates (where n = 1, 3) is shown. In the range of concentrations of phosphoric acid in the aqueous phase from 6 to 11 M, the values of equilibrium constants are estimated, which describe the processes and reactions occurring in the system: stepwise dissociation of acid, distribution of TBP, formation of solvates of phosphoric acid, distribution of the resulting solvates of acid, displacement of ionic equilibria in aqueous phase. Mathematically these processes are taken into account using the law of mass action and the equations of material balance. It is believed that the system has established an equilibrium corresponding to a given temperature and pressure. The calculated values of solvate concentrations are in satisfactory agreement with experimental data.

Determination of activity coefficients of aqueous solutions of urea in the ultracentrifuge

1970 ◽  
Vol 23 (5) ◽  
pp. 915
Author(s):  
EF Woods
Keyword(s):  
Aqueous Solutions ◽  
Activity Coefficients ◽  
Similar Type ◽  
Point Of View ◽  
Published Data ◽  
Molecular Weights ◽  
Equilibrium Sedimentation ◽  
Aqueous Urea ◽  
Determination Of Activity

Apparent molecular weights of aqueous urea solutions have been determined by equilibrium sedimentation over the concentration range 1-9M. At the speeds used in the ultracentrifuge (39460 to 67770 r.p.m.) there was evidence of the effect of pressure on the sedimentation of urea. Apparent molecular weights of urea were therefore calculated at the solution-air meniscus where the solution is at l atm. The derived activity coefficients showed a similar type of oncentration dependence to published data for urea but there were significant quantitative differences. The significance of the results from the point of view of calculating theoretical distributions in the ultracentrifuge is discussed.

Determination of single ion activities by relying on the electrical double layer model: NaF aqueous solutions

1981 ◽  
Vol 59 (13) ◽  
pp. 1925-1932 ◽  
Author(s):  
Anna Daghetti ◽  
Sergio Trasatti
Keyword(s):  
Aqueous Solutions ◽  
Activity Coefficients ◽  
Potential Drop ◽  
Real Activity ◽  
Solution Interface ◽  
Double Layer Model ◽  
Ion Activities ◽  
Single Ion Activity ◽  
Specific Adsorption Of Ions

Single ion activity coefficients for aqueous solutions of NaF in the range m = 0.1 up to m = 0.9 mol kg−1 have been derived by measuring the potential difference of the cell Hg (σ = const)/NaF(m)/F−-selective electrode. The approach rests on the assumption that the electric potential drop across the Hg/solution interface is independent of the electrolyte concentration once the diffuse layer effects are accounted for by the Gouy–Chapman theory, provided specific adsorption of ions is absent. The derived γ− values have been compared with the "real" activity coefficients as determined by Rabinovich and Titov and with the predictions of the hydration theory of Bates and Robinson. It is shown that the latter do not agree with the present experimental observations. Possible reasons for this apparent discrepancy are discussed.

scholarly journals Determination of micro-quantities of magnesium.

1962 ◽  
Vol 10 (2) ◽  
pp. 154-156
Author(s):  
J.C. Van Schouwenburg ◽  
I. Walinga
Keyword(s):  
Boric Acid ◽  
Organic Phase ◽  
Water Phase ◽  
Reagent Blank ◽  
Acid Buffer

To 25 ml or less of a neutral sample (containing up to 20 gamma Mg) in a 150ml separating funnel, 10 ml tartrate solution, 10 ml boric-acid buffer and 5 ml Na diethyldithiocarbamate are added and the solution made up to 50 ml. After extracting with 25 ml chloroform and discarding the organic phase the water phase is rinsed with about 10 ml chloroform and the organic phase again discarded. 10 ml of masking agent, 1 ml n-butylamine and 10 ml extracting solution (8-hydroxyquinoline in chloroform) are then added. After shaking and separating the organic phase a knife point of Na2SO4 is added and the extinction of the samples and that of a l0 gamma Mg standard are measured against a simultaneously treated reagent blank at 380 nm. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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