Extraction of Alkali Metal and Ammonium Dipicrylaminates into Nitrobenzene in the Presence of Some Acyclic Polyethers

1992 ◽  
Vol 57 (2) ◽  
pp. 276-288 ◽  
Author(s):  
Emanuel Makrlík ◽  
Jaroslava Hálová ◽  
Petr Vaňura
Keyword(s):  
Alkali Metal ◽  
Equilibrium Constants ◽  
Phase System ◽  
Two Phase ◽  
Nitrobenzene Phase ◽  
Chemical Equilibria ◽  
Peg 400 ◽  
Maximum Value ◽  
The Stability ◽  
Crystallographic Radius

The effect of the presence of six different acyclic polyethers (2-glym, 3-glym, 4-glym, PEG 200, PEG 300 and PEG 400), denoted by L, on the distribution of alkali metal dipicrylaminates and ammonium dipicrylaminate (MA) between the aqueous and nitrobenzene phases has been studied. The two-phase system can be quantitatively described by the following five chemical equilibria: Ma+ + Aa- + L0 ↔ MLa+ + Aa-,Ma+ + Aa- ↔ M0+ + A0-, MLA0 ↔ ML0+ + A0-, MA0 ↔ M0+ + A0-, La ↔ L0, for which the respective equilibrium constants Kex(ML+, A-), Kex(M+, A-), Kd0(MLA), Kd0(MA) and KD were determined. The values of Kex(ML+,A-) increase with the increasing crystallographic radius of the M+ ion and with the number of oxyethylene units in the molecule of the ligand, L, in the series 2-glym < 3-glym < 4-glym < PEG 200 < PEG 300 < PEG 400. In addition, it has been demonstrated that the stability of the ML0+ species in the nitrobenzene phase has a maximum value for M+ = Na+ for all the studied ligands. The presence of the polyethers is detrimental to the separation of Cs+ from the other cations, but improves the separation of Na+ from Li+. The extraction selectivities for the K+/NH4+, K+/Li+ and NH4+/Li+ pairs was not significantly affected by the presence of the ligands, except for 2-glym.

scholarly journals Stability of the barium-benzo-15-crown-5 complex in nitrobenzene saturated with water

2006 ◽  
Vol 71 (11) ◽  
pp. 1147-1151 ◽  
Author(s):  
E. Makrlík ◽  
P. Vaňura
Keyword(s):  
Stability Constant ◽  
Aqueous Phase ◽  
Extraction Constant ◽  
Two Phase ◽  
Nitrobenzene Phase ◽  
Activity Measurements ◽  
System L ◽  
Exchange Extraction ◽  
Phase Water ◽  
The Stability

From extraction experiments and ?-activity measurements, the exchange extraction constant corresponding to the equilibrium Ba2+(aq) + SrL2 2+(nb) _ BaL 2 2+(nb) + Sr2+(aq) occurring in the two-phase water-nitrobenzene system (L = benzo-15-crown-5; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K ex (Ba2+, SrL22+) = 0.3 ? 0.1. Furthermore, the stability constant of the benzo-15-crown-5-barium complex in nitrobenzene saturated with water was calculated for the temperature of 25 ?C: log ?nb (BaL2 2+) = 13.3?0.1.

On the Equilibrium of Cavitation Nuclei in Liquid-Gas Solutions

1981 ◽  
Vol 103 (3) ◽  
pp. 425-430 ◽  
Author(s):  
Y. S. Cha
Keyword(s):  
Stable Equilibrium ◽  
Thermodynamic Theory ◽  
Phase System ◽  
Saturated Liquid ◽  
Theoretical Justification ◽  
Two Phase ◽  
System Pressure ◽  
Two Component ◽  
Cavitation Nuclei ◽  
The Stability

The stability of a spherical bubble in a two-component two-phase system is examined by employing the thermodynamic theory of dilute solutions. It is shown that a bubble can remain in a state of stable equilibrium provided that the ratio of the total number of moles of the solute to the total number of moles of the solvent in the system is not extremely small and that the system pressure falls between an upper bound (dissolution limit) and a lower bound (cavitation limit). The results of the analysis provide a theoretical basis for the persistence of microbubbles in a saturated liquid-gas solution. Thus to a certain extent, the results also help to resolve the dilemma that exists in the field of cavitation due to (1) the necessity of postulating the existence of microbubbles; and (2) the lack of theoretical justification for the persistence of such bubbles in a liquid.

scholarly journals Solvent extraction of Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+, Mn2+, Co2+ and Ni2+ into nitrobenzene using strontium dicarbollylcobaltate and tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate

2008 ◽  
Vol 73 (12) ◽  
pp. 1181-1186 ◽  
Author(s):  
E. Makrlík ◽  
J. Budka ◽  
P. Vaňura ◽  
P. Selucký
Keyword(s):  
Two Phase ◽  
Nitrobenzene Phase ◽  
Tert Butyl ◽  
Cation Order ◽  
Activity Measurements ◽  
Extraction Constants ◽  
Exchange Extraction ◽  
Phase Water ◽  
The Stability ◽  
Water Saturated

The exchange extraction constants corresponding to the general equilibrium M2+(aq) + SrL2+(nb) ? ?ML2+(nb) + Sr2+(aq) occurring in the two- -phase water-nitrobenzene system (M2+ = Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+ , Mn2+, Co2+ or Ni2+; L = tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate; aq = aqueous phase; nb = nitrobenzene phase) were evaluated from extraction experiments and ?-activity measurements. Furthermore, the stability constants of the ML2+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order Ba2+ < Mn2+ < Pb2+, Co2+ < Cu2+, Zn2+ < Cd2+, Ni2+ < UO22+ < Ca2+.

Extraction and stability of selected proteins in ionic liquid based aqueous two phase systems

2014 ◽  
Vol 16 (5) ◽  
pp. 2670-2679 ◽  
Author(s):  
Rupali K. Desai ◽  
Mathieu Streefland ◽  
Rene H. Wijffels ◽  
Michel H. M. Eppink
Keyword(s):  
Ionic Liquid ◽  
Aqueous Solutions ◽  
Phase System ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
Aqueous Two Phase Systems ◽  
Phase Systems ◽  
The Stability

This article discusses the extraction of Rubisco in an ionic liquid (IL) based aqueous two phase system and the stability of proteins in aqueous solutions of IL.

Chemical equilibria including particles I-, I3-, I5-, and I2 in two-phase water-nitrobenzene extraction system

1990 ◽  
Vol 55 (11) ◽  
pp. 2602-2605 ◽  
Author(s):  
Emanuel Makrlík
Keyword(s):  
Thermodynamic Parameters ◽  
Aqueous Phase ◽  
Equilibrium Constants ◽  
Extraction System ◽  
Two Phase ◽  
Chemical Equilibria ◽  
Phase Water ◽  
General Relations ◽  
Homogeneous Reactions

General relations among thermodynamic parameters characterizing chemical equilibria with species I-, I3-, I5-, and I2 in the two-phase water-nitrobenzene extraction system have been derived. Furthermore, these relations have been used for calculating equilibrium constants K1aq(I3-) and K2aq(I5-) corresponding to homogeneous reactions I-(aq) + I2(aq) ⇄ I3-(aq) and I3-(aq) + I2(aq) ⇄ I5-(aq) proceeding in the aqueous phase of the system under study. Finally, stability of polyiodides I3- and I5- in both phases has been discussed.

scholarly journals Extraction of calcium from water into nitrobenzene using strontium dicarbollylcobaltate in the presence of 18-crown-6

2000 ◽  
Vol 65 (4) ◽  
pp. 275-279
Author(s):  
Marcela Danková ◽  
Emanuel Makrlík ◽  
Petr Vanura
Keyword(s):  
Stability Constant ◽  
Aqueous Phase ◽  
Extraction Constant ◽  
Two Phase ◽  
Nitrobenzene Phase ◽  
Activity Measurements ◽  
System L ◽  
Phase Water ◽  
The Stability

From extraction experiments and g-activity measurements, the extraction constant corresponding to the equilibrium Ca 2+ (aq)+ SrL 2+ (nb) === CaL 2+ (nb) + Sr 2+ (aq) taking place in the two-phase water-nitrobenzene system(L= 18-crown-6, aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex(Ca 2+, SrL 2+) = -1.9 ?0.1. Furthermore, the stability constant of the calcium - 18-crown-6 complex in nitrobenzene saturated with water was calculated for the temperature of 25?C: log bnb (CaL 2+)=10.1?0.1.

Preparation and Characterisation of Graphene Nanofluid: To Be Used As Coolant

2020 ◽  
Author(s):  
Senthil Kumar Velukkudi Santhanam ◽  
Dolly Austen Thomas ◽  
Mystica Augustine Michael Duke ◽  
Viswanathan Doraiswamy
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Base Fluid ◽  
Solid Phase ◽  
Nano Particles ◽  
Planar Geometry ◽  
Phase System ◽  
Transfer Coefficients ◽  
Two Phase ◽  
The Stability

Abstract In the recent years, nanofluids embarked as a new class of fluids with improved thermophysical properties such as thermal conductivity, thermal diffusivity, viscosity, and convective heat transfer coefficients thus promoting better heat transfer. Nanofluids consists of two-phase system where the nano sized solid phase (nanoparticles) is dispersed into a base fluid. Graphene is a material which has two-dimensional planar geometry with thermal conductivity of the order of 5000 W/mK. Nanoparticles in the form of thin flakes as small as 50 nm, 100 nm has been used in this study. Two step technique is the used method for preparing nanofluids. Inclusion of additives in small quantity, enhance the durability of the nano particles inside the conventional base fluids. The stability of the solid nano particles inside the conventional base fluid is increased by using surfactants. The heat transfer capacity and stability of the fluids are considered as the basic properties for investigation. The nanofluids characterization studies were drawn from the SEM, XRD and thermal conductivity results. Hot wire method was used to determine the thermal conductivity of the nanofluids. The preparation and properties of graphene based nanofluids which can be used as coolant are studied in this work.

scholarly journals Complexation of some univalent organic cations with benzo-18-crown-6 in nitrobenzene saturated with water

2012 ◽  
Vol 10 (5) ◽  
pp. 1495-1499
Author(s):  
Emanuel Makrlík ◽  
Petr Vaňura ◽  
Pavel Selucký
Keyword(s):  
Cationic Complex ◽  
Two Phase ◽  
Complex Species ◽  
Nitrobenzene Phase ◽  
Cation Order ◽  
Activity Measurements ◽  
Extraction Constants ◽  
Univalent Organic Cations ◽  
Phase Water ◽  
The Stability

AbstractFrom extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium C+(aq) + 1·Na+(nb) 1·C+ (nb) + Na+(aq) taking place in the two-phase water-nitrobenzene system (C+ = methylammonium, ethylammonium, propylammonium, ethanolammonium, diethanolammonium, triethanolammonium, cation TRIS+, hydrazinium, hydroxylammonium; 1 = benzo-18-crown-6; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the 1·C+ cationic complex species in nitrobenzene saturated with water were calculated; they were found to increase in the following cation order: triethanolammonium +

An experimental investigation of stability and interfacial waves in co-current flow of two liquids

1965 ◽  
Vol 22 (2) ◽  
pp. 217-224 ◽  
Author(s):  
M. E. Charles ◽  
L. U. Lilleleht
Keyword(s):  
Reynolds Number ◽  
Water Layer ◽  
High Water ◽  
Water Phase ◽  
Transition To Turbulence ◽  
Phase System ◽  
Interfacial Waves ◽  
Mean Flow ◽  
Two Phase ◽  
The Stability

The stability of the co-current stratified flow of oil and water was investigated experimentally in a horizontal rectangular conduit. Laminar-turbulent transitions were determined for both phases. With the two-phase system the transition to turbulence in the water phase occurred at a higher Reynolds number in the presence of a laminar oil layer provided the input water-to-oil ratio was relatively high, while the transition in the oil phase took place at a lower Reynolds number in the presence of a turbulent water layer. The appearance of first interfacial waves coincided with the transition to turbulence of the less viscous or water phase. This suggests that in the system investigated the resonance mechanism as proposed by Phillips (1957) was responsible for the generation of these first waves. However, at relatively high water flow rates and water-to-oil ratios more pronounced waves were observed which appeared to be generated by an instability in the mean flow.

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