Sorption of Copper Species from Organic Solutions on Anion Exchangers. Part I: Sorption on the Bromide form of the Exchanger

1971 ◽  
Vol 9 (4) ◽  
pp. 499-507 ◽  
Author(s):  
R. Cohen
Keyword(s):  
Anion Exchangers ◽  
Copper Species ◽  
Bromide Form ◽  
Organic Solutions

Imidazole Promoted Efficient Anomerization of β-D-Glucose Pentaacetate in Organic Solutions and Solid State

2019 ◽  
Author(s):  
Meifeng Wang ◽  
Liyin Zhang ◽  
Yiqun Li ◽  
Liuqun Gu
Keyword(s):  
Solid State ◽  
Organic Solvents ◽  
Room Temperature ◽  
Materials Design ◽  
The Future ◽  
Organic Solutions ◽  
Glucose Pentaacetate

<p></p>Anomerization of glycosides were rarely performed under basic condition due to lack of efficiency. Here an imidazole promoted anomerization of β-D-glucose pentaacetate was developed; and reaction could proceed in both organic solvents and solid state at room temperature. Although mechanism is not yet clear, this unprecedent mild anomerization in solid state may open a new promising way for stereoseletive anomerization of broad glucosides and materials design in the future..

Cr(VI) RETENTION CAPACITY AND SELECTIVITY OF SOME STRONG AND WEAK BASE ANION EXCHANGERS

2004 ◽  
Vol 3 (3) ◽  
pp. 221-230 ◽  
Author(s):  
Ion Untea ◽  
Cristina Orbeci ◽  
Elena Tudorache ◽  
Violeta Neagu
Keyword(s):  
Weak Base ◽  
Anion Exchangers ◽  
Retention Capacity

The Influence of Benthic Biota on Copper Speciation and Distribution in Freshwater-Sediment Systems

1981 ◽  
Vol 16 (1) ◽  
pp. 45-58 ◽  
Author(s):  
G. Krantzberg ◽  
P.M. Stokes
Keyword(s):  
Freshwater Sediment ◽  
Benthic Macroinvertebrate ◽  
Macroinvertebrate Communities ◽  
Copper Species ◽  
Copper Speciation ◽  
Physico Chemical ◽  
Macro Benthos

Abstract An investigation was made of the effects exerted by benthic macroinvertebrate communities on copper speciation in sediments from a lake which is becoming acidified. In laboratory microcosms, benthic macroinvertebrate communities stimulated the flux of copper from sediment to water. The presence of the macro-benthos resulted in a redistribution of physico-chemical copper species within the sediment with a transfer from more strongly complexed forms (HC1 extractable) to adsorbed and cation exchangeable forms (MgCl2 extractable). The role of bio-turbation in copper transformations is discussed.

scholarly journals Neptunium extraction by N,N-dialkylamides

2020 ◽  
Vol 108 (9) ◽  
pp. 707-716
Author(s):  
Jarrod M. Gogolski ◽  
Peter R. Zalupski ◽  
Travis S. Grimes ◽  
Mark P. Jensen
Keyword(s):  
Nitric Acid ◽  
Solvent Extraction ◽  
Radioactive Waste ◽  
Partial Oxidation ◽  
Acid Solutions ◽  
Nitric Acid Solutions ◽  
Organic Solutions

AbstractSeparation of neptunium by solvent extraction has been based on tributylphosphate (TBP) for decades, but TBP is not fully incinerable, which adds to the burden of long-lived radioactive waste. Alternatives to TBP for uranium and plutonium extraction, such as the N,N-diakylamides, previously have been explored in the hopes of transitioning to an extractant that is incinerable. Four N,N-diakylamides, N,N-dihexylhexanamide (DHHA), N,N-dihexyloctanamide (DHOA), N,N-di(2-ethylhexyl)butanamide (DEHBA), and N,N-di(2-ethylhexyl)-iso-butanamide (DEHiBA) were considered in this work for their potential to extract millimolar concentrations of Np(IV), Np(V), and Np(VI) from nitric acid solutions into organic solutions containing 1 M extractant in Exxsol D60. Under these conditions the branching of the alkyl substituents affects the extractability of Np(VI) and Np(IV), causing three of the dialkylamides, DHHA, DHOA and DEHBA, to extract neptunium in the expected order Np(VI) > Np(IV) > > Np(V). In contrast, branched DEHiBA is so poor an extractant for Np(IV) that the extraction order becomes Np(VI) > > Np(V) > Np(IV) between 0.1 and 5.6 M HNO3 due to partial oxidation of the Np(V) in nitric acid.

scholarly journals Amphiphile Organization in Organic Solutions: An Alternative Explanation for Small-Angle X-ray Scattering Features in Malonamide/Alkane Mixtures

2020 ◽  
Vol 124 (47) ◽  
pp. 10822-10831
Author(s):  
Michael J. Servis ◽  
Marek Piechowicz ◽  
Ilya A. Shkrob ◽  
L. Soderholm ◽  
Aurora E. Clark
Keyword(s):  
Small Angle ◽  
Alternative Explanation ◽  
X Ray ◽  
X Ray Scattering ◽  
Organic Solutions ◽  
Ray Scattering

scholarly journals Ferrierite and Its Delaminated Forms Modified with Copper as Effective Catalysts for NH3-SCO Process

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4885
Author(s):  
Aneta Święs ◽  
Małgorzata Rutkowska ◽  
Andrzej Kowalczyk ◽  
Urbano Díaz ◽  
Antonio E. Palomares ◽  
...  
Keyword(s):  
Copper Oxide ◽  
Ammonia Oxidation ◽  
Catalytic Reduction ◽  
Surface Acidity ◽  
Selective Reduction ◽  
Exchange Method ◽  
Copper Species ◽  
Selective Catalytic Oxidation ◽  
Catalytically Active ◽  
Copper Cations

Ferrierites and their delaminated forms (ITQ-6), containing aluminum or titanium in the zeolite framework, were synthetized and modified with copper by an ion-exchange method. The obtained samples were characterized with respect to their chemical composition (ICP-OES), structure (XRD, UV-Vis DRS), textural parameters (N2-sorption), surface acidity (NH3-TPD), form and reducibility of deposited copper species (UV-Vis DRS and H2-TPR). Ferrierites and delaminated ITQ-6 zeolites modified with copper were studied as catalysts for the selective catalytic oxidation of ammonia to dinitrogen (NH3-SCO). It was shown that aggregated copper oxide species, which were preferentially formed on Ti-zeolites, were catalytically active in direct low-temperature ammonia oxidation to NO, while copper introduced into Al-zeolites was present mainly in the form of monomeric copper cations catalytically active in selective reduction of NO by ammonia to dinitrogen. It was postulated that ammonia oxidation in the presence of the studied catalysts proceeds according to the internal-selective catalytic reduction mechanism (i-SCR) and therefore the suitable ratio between aggregated copper oxide species and monomeric copper cations is necessary to obtain active and selective catalysts for the NH3-SCO process. Cu/Al-ITQ-6 presented the best catalytic properties possibly due to the most optimal ratio of these copper species.

scholarly journals Characterization and Structural Insights of the Reaction Products by Direct Leaching of the Noble Metals Au, Pd and Cu with N,N′-Dimethyl-piperazine-2,3-dithione/I2 Mixtures

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4721
Author(s):  
Angela Serpe ◽  
Luca Pilia ◽  
Davide Balestri ◽  
Luciano Marchiò ◽  
Paola Deplano
Keyword(s):  
Density Functional ◽  
Noble Metals ◽  
Density Functional Theory Calculations ◽  
Metal Powders ◽  
Reaction Products ◽  
Metal Recycling ◽  
Direct Leaching ◽  
Tetrahedral Complexes ◽  
Organic Solutions ◽  
Structural Insights

In the context of new efficient and safe leaching agents for noble metals, this paper describes the capability of the Me2pipdt/I2 mixture (where Me2pipdt = N,N′-dimethyl-piperazine-2,3-dithione) in organic solutions to quantitatively dissolve Au, Pd, and Cu metal powders in mild conditions (room temperature and pressure) and short times (within 1 h in the reported conditions). A focus on the structural insights of the obtained coordination compounds is shown, namely [AuI2(Me2pipdt)]I3 (1), [Pd(Me2pipdt)2]I2 (2a) and [Cu(Me2pipdt)2]I3 (3), where the metals are found, respectively, in 3+, 2+ and 1+ oxidation states, and of [Cu(Me2pipdt)2]BF4 (4) and [Cu(Me2dazdt)2]I3 (5) (Me2dazdt = N,N′-dimethyl-perhydrodizepine-2,3-dithione) compared with 3. Au(III) and Pd(II) (d8 configuration) form square–planar complexes, whereas Cu(I) (d10) forms tetrahedral complexes. Density functional theory calculations performed on the cationic species of 1–5 help to highlight the nature of the bonding in the different complexes. Finally, the valorization of the noble metals-rich leachates is assessed. Specifically, gold metal is quantitatively recovered from the solution besides the ligands, showing the potential of these systems to promote metal recycling processes.

scholarly journals Autocatalytic photoredox Chan-Lam coupling of free diaryl sulfoximines with arylboronic acids

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cong Wang ◽  
Hui Zhang ◽  
Lucille A. Wells ◽  
Tian Liu ◽  
Tingting Meng ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Hydrogen Atom Abstraction ◽  
Coupling Reactions ◽  
Ambient Light ◽  
Environmental Friendliness ◽  
Copper Species ◽  
Arylboronic Acids ◽  
Ligand Free ◽  
Byproduct Formation ◽  
Electron Reduction

AbstractN-Arylation of NH-sulfoximines represents an appealing approach to access N-aryl sulfoximines, but has not been successfully applied to NH-diaryl sulfoximines. Herein, a copper-catalyzed photoredox dehydrogenative Chan-Lam coupling of free diaryl sulfoximines and arylboronic acids is described. This neutral and ligand-free coupling is initiated by ambient light-induced copper-catalyzed single-electron reduction of NH-sulfoximines. This electron transfer route circumvents the sacrificial oxidant employed in traditional Chan-Lam coupling reactions, increasing the environmental friendliness of this process. Instead, dihydrogen gas forms as a byproduct of this reaction. Mechanistic investigations also reveal a unique autocatalysis process. The C–N coupling products, N-arylated sulfoximines, serve as ligands along with NH-sulfoximine to bind to the copper species, generating the photocatalyst. DFT calculations reveal that both the NH-sulfoximine substrate and the N-aryl product can ligate the copper accounting for the observed autocatalysis. Two energetically viable stepwise pathways were located wherein the copper facilitates hydrogen atom abstraction from the NH-sulfoximine and the ethanol solvent to produce dihydrogen. The protocol described herein represents an appealing alternative strategy to the classic oxidative Chan-Lam reaction, allowing greater substrate generality as well as the elimination of byproduct formation from oxidants.

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