Understanding “On-Water” Catalysis of Organic Reactions. Effects of H+ and Li+ Ions in the Aqueous Phase and Nonreacting Competitor H-Bond Acceptors in the Organic Phase: On H2O versus on D2O for Huisgen Cycloadditions

2015 ◽  
Vol 80 (3) ◽  
pp. 1809-1817 ◽  
Author(s):  
Richard N. Butler ◽  
Anthony G. Coyne
Keyword(s):  
Aqueous Phase ◽  
Organic Phase ◽  
Organic Reactions ◽  
Water Catalysis

Extraction of hafnium(IV) with organophosphorus reagents from solutions of mineral acids mixtures

1979 ◽  
Vol 44 (12) ◽  
pp. 3656-3664
Author(s):  
Oldřich Navrátil ◽  
Jiří Smola ◽  
Rostislav Kolouch
Keyword(s):  
Ionic Strength ◽  
Aqueous Phase ◽  
Organic Phase ◽  
Perchloric Acid ◽  
Synergic Effect ◽  
Salting Out ◽  
Initial Concentration ◽  
Mixed Complexes ◽  
Synergic Extraction ◽  
Mineral Acids

Extraction of hafnium(IV) was studied from solutions of mixtures of perchloric and nitric acids and of perchloric and hydrochloric acids for constant ionic strength, I = 2, 4, 6, or 8, and for cHf 4 . 10-4 mol l-1. The organic phase was constituted by solutions of some acidic or neutral organophosphorus reagents or of 2-thenoyltrifluoroacetone, 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone, or N-benzoyl-N-phenylhydroxylamine in benzene, chloroform, or n-octane. A pronounced synergic extraction of hafnium proceeds only on applying organophosphorus reagents from an aqueous phase whose acidity is not lower than 3M-(HClO4 + HNO3) or 5M-(HClO4 + HCl). The synergic effect was not affected markedly by a variation of the initial concentration of hafnium in the range 1 . 10-8 -4 .10-4 mol l-1, it lowered with increasing initial concentration of the organophosphorus reagent and decreasing concentration of the H+ ions. It is suggested that the hafnium passes into the organic phase in the form of mixed complexes, the salting-out effect of perchloric acid playing an appreciable part.

Recovery of Uranium (VI) from Water Solutions by Membrane Extraction

2013 ◽  
Vol 704 ◽  
pp. 66-71
Author(s):  
Grazyna Zakrzewska ◽  
Pawel Bieluszka ◽  
Ewelina Chajduk ◽  
Stanislaw Wolkowicz
Keyword(s):  
Aqueous Phase ◽  
Organic Phase ◽  
Extraction Efficiency ◽  
Membrane Extraction ◽  
Membrane Contactor ◽  
Shell Side ◽  
Real Solutions ◽  
Model Solutions ◽  
Capillary Membrane ◽  
Capillary Membranes

The extraction of uranium from aqueous model solutions, as well as from real solutions reulting from leaching uranium ores was carried out in the system equipped with the Liqui-Cel® Extra-Flow membrane contactor with polypropylene capillary membranes. D2EHPA in toluene was used as an organic phase. Different arrangements of flow inside the membrane module were tested. The better approach appeared to be the arrangement with aqueous phase in the shell side of the contactor and organic phase inside the capillary membrane. The extraction efficiency for model solutions reached 95% and 87% for real post-leaching liquors.

The extraction of cobalt(II) from lithium chloride solutions by aliquat 336R dissolved in chloroform

1982 ◽  
Vol 35 (11) ◽  
pp. 2345 ◽  
Author(s):  
R Paimin ◽  
RW Cattrall
Keyword(s):  
Ion Exchange ◽  
Aqueous Phase ◽  
Lithium Chloride ◽  
Organic Phase ◽  
Equilibrium Constants ◽  
Single Drop ◽  
Chloride Solutions ◽  
Rate Determining Step ◽  
Fast Ion ◽  
Drop Technique

The extraction of cobalt(II) by Aliquat 336R from 7 M lithium chloride solutions involves two species from the aqueous phase, COCl42 and CoCl3-, with the former being the predominant one. The equilibrium constants for the formation of the extracted complexes (R3MeN+)2 CoCl42- and R3MeN+CoCI3- are: logKll 5.01 and logK12 9.55. From the results of experiments by means of the single-drop technique, a mechanism is proposed based on the formation of interfacial complexes by fast ion-exchange with a rate-determining step which involves the replacement at the interface of the complex (R3MeN+)2 COCl42- by two molar proportions of reagent from the bulk organic phase.

Electrospun polystyrene nanofibers as a novel adsorbent to transfer an organic phase from an aqueous phase

2016 ◽  
Vol 39 (7) ◽  
pp. 1326-1330 ◽  
Author(s):  
Feilong Liu ◽  
Dandan Song ◽  
Xueying Huang ◽  
Hui Xu
Keyword(s):  
Aqueous Phase ◽  
Organic Phase

scholarly journals Fabrication of Microparticles with Front–Back Asymmetric Shapes Using Anisotropic Gelation

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1121
Author(s):  
Dongkyu Lee ◽  
Hiroyuki Kitahata ◽  
Hiroaki Ito
Keyword(s):  
Velocity Field ◽  
Sodium Alginate ◽  
Stagnation Point ◽  
Calcium Chloride ◽  
Aqueous Phase ◽  
Microfluidic Device ◽  
Organic Phase ◽  
Fabrication Technique ◽  
Flow Focusing ◽  
Asymmetric Shape

Droplet-based microfluidics is a powerful tool for producing monodispersed micrometer-sized droplets with controlled sizes and shapes; thus, it has been widely applied in diverse fields from fundamental science to industries. Toward a simpler method for fabricating microparticles with front–back asymmetry in their shapes, we studied anisotropic gelation of alginate droplets, which occurs inside a flow-focusing microfluidic device. In the proposed method, sodium alginate (NaAlg) aqueous phase fused with a calcium chloride (CaCl2) emulsion dispersed in the organic phase just before the aqueous phase breaks up into the droplets. The fused droplet with a front–back asymmetric shape was generated, and the asymmetric shape was kept after geometrical confinement by a narrow microchannel was removed. The shape of the fused droplet depended on the size of prefused NaAlg aqueous phase and a CaCl2 emulsion, and the front–back asymmetry appeared in the case of the smaller emulsion size. The analysis of the velocity field inside and around the droplet revealed that the stagnation point at the tip of the aqueous phase also played an important role. The proposed mechanism will be potentially applicable as a novel fabrication technique of microparticles with asymmetric shapes.

scholarly journals The Preparation of High-Performance and Stable MXene Nanofiltration Membranes with MXene Embedded in the Organic Phase

Membranes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 2
Author(s):  
Qiang Xue ◽  
Kaisong Zhang
Keyword(s):  
Aqueous Phase ◽  
Organic Phase ◽  
Negative Charge ◽  
Interfacial Polymerization ◽  
Water Immersion ◽  
Membrane Surface ◽  
Polymerization Reaction ◽  
Future Research ◽  
Separation Performance ◽  
Nanofiltration Membranes

Nanomaterials embedded in nanofiltration membranes have become a promising modification technology to improve separation performance. As a novel representation of two-dimensional (2D) nanomaterials, MXene has nice features with a strong negative charge and excellent hydrophilicity. Our previous research showed that MXene nanosheets were added in the aqueous phase, which enhanced the permeselectivity of the membrane and achieved persistent desalination performance. Embedding the nanomaterials into the polyamide layer through the organic phase can locate the nanomaterials on the upper surface of the polyamide layer, and also prevent the water layer around the hydrophilic nanomaterials from hindering the interfacial polymerization reaction. We supposed that if MXene nanosheets were added in the organic phase, MXene nanosheets would have more negative contact sites on the membrane surface and the crosslinking degree would increase. In this study, MXene were dispersed in the organic phase with the help of ultrasound, then MXene nanocomposite nanofiltration membranes were achieved. The prepared MXene membranes obtained enhanced negative charge and lower effective pore size. In the 28-day persistent desalination test, the Na2SO4 rejection of MXene membrane could reach 98.6%, which showed higher rejection compared with MXene embedded in aqueous phase. The results of a long-time water immersion test showed that MXene membrane could still maintain a high salt rejection after being soaked in water for up to 105 days, which indicated MXene on the membrane surface was stable. Besides MXene membrane showed high rejection for high-concentration brine and good mono/divalent salt separation performance in mono/divalent mixed salt solutions. As a part of the study of MXene in nanofiltration membranes, we hoped this research could provide a theoretical guidance for future research in screening different addition methods and different properties.

scholarly journals Ion-Specific Clustering of Metal-Amphiphile Complexes in Rare Earth Separations

2020 ◽  
Author(s):  
Srikanth Nayak ◽  
Kaitlin Lovering ◽  
Ahmet Uysal
Keyword(s):  
Aqueous Phase ◽  
Organic Phase ◽  
Immiscible Liquids ◽  
X Ray ◽  
Clustering Model ◽  
X Ray Scattering ◽  
Heavy Lanthanides ◽  
Complex Fluid ◽  
Nanoscale Structure ◽  
Ray Scattering

Aggregation and clustering of metal-amphiphile complexes formed during solvent extraction of lanthanides have been studied with small angle X-ray scattering. The nanoscale structure of the complex fluid strongly depends on the counter-ion (NO<sub>3</sub><sup>-</sup> or SCN<sup>-</sup>) and the lanthanide being extracted. As a result, it is possible to selectively transport light or heavy lanthanides from the aqueous phase into the organic phase by simply choosing NO<sub>3</sub><sup>-</sup> or SCN<sup>-</sup> as the background anion, respectively. While the organic phase containing TOMA-NO<sub>3</sub> always shows clustering, indicating the presence of stronger attractive interactions between metal-amphiphile aggregates, TOMA-SCN shows clustering as a function of the metal loading. These qualitative differences suggest that the extraction efficiency is driven by the aqueous phase conditions in NO<sub>3</sub><sup>-</sup> solutions, while it is driven by the organic phase structuring in SCN<sup>-</sup> solutions. A clustering model, that accounts for the hard sphere repulsions and short-range attractions between the aggregates, has been developed to model the X-ray scattering results. The new model successfully describes the nanoscale structure and helps understanding the mechanisms responsible for amphiphile assisted ion transport and complexation between immiscible liquids.

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