2,2-Disubstituted-4,4-dimethylimidazolidinyl-3-oxy nitroxides: indicators of aqueous acidity through variation of aN with pH

1982 ◽  
Vol 104 (3) ◽  
pp. 827-830 ◽  
Author(s):  
John F. W. Keana ◽  
Michael J. Acarregui ◽  
Sharyl L. M. Boyle
Keyword(s):  
Aqueous Acidity

scholarly journals Solvent Extraction of Fe(III) from Aqueous Chloride Solution by Cyanex 301 Dissolved in Kerosene

2010 ◽  
Vol 3 (1) ◽  
pp. 97 ◽  
Author(s):  
R. K. Biswas ◽  
M. R. Ali ◽  
M. A. Habib ◽  
S. M. A. Salam ◽  
A. K. Karmakar ◽  
...  
Keyword(s):  
Equilibration Time ◽  
Extractant Concentration ◽  
Extraction Equilibrium ◽  
Wide Range ◽  
Aqueous Chloride Solution ◽  
Title System ◽  
Aqueous Chloride ◽  
Cyanex 301 ◽  
Extraction Mechanisms ◽  
Aqueous Acidity

The title system has been investigated over a wide range of aqueous acidity. The equilibration time is 1 h. The extraction ratio (D) is independent of [Fe(III)] provided equilibrium [HCl] and [HA] are kept constant. At a constant equilibrium extractant concentration, the [HCl] dependences are -1.6, ~0 and -3 in the [HCl] regions of >3, 2-0.5 and <0.3 M; respectively; whilst at constant [HCl], the [HA] dependence is 3.0. On the other hand, [Cl-] dependence varies within -0.5 to -3 at constant [HCl] of 0.3 M; whereas its values are ~ -1 and ~ 0.63 at constant [HCl] of 3 and 1 M, respectively. Based on these results the extraction mechanisms have been suggested to be + 3 HA(o) ? FeA3(o) + n Cl- + 3 H+ in the low [HCl] region,    + 3 HA(o) + n Cl- ? FeCl3.3HA(o) in the intermediate [HCl] region and HFeCl4 + 3 HA(o) ? FeCl3.3HA(o) + HCl in the high [HCl] region under investigation. The Kex  and ΔH values have been evaluated. Loading capacity is 5.5 g Fe(III)/100 g Cyanex 301. The stripping can be made effective by a mixture of 6 M H2SO4 and 1 M Na2C2O4.Keywords:  Extraction equilibrium; Fe(III) extraction; Cyanex 301; chloride medium.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:10.3329/jsr.v3i1.6263                 J. Sci. Res. 3 (1), 97-109 (2011)

Complexation of a macrocyclic ligand, 2,6-di (N-methyl)formamide-calix[4]pyridine, with Eu(III) and extraction of Eu(III) and Am(III)

2018 ◽  
Vol 106 (4) ◽  
pp. 301-310
Author(s):  
Lina Lü ◽  
Jun Liu ◽  
Yanqiu Yang ◽  
Kun Li ◽  
Sheng Hu ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Macrocyclic Ligand ◽  
Macrocyclic Compound ◽  
Aprotic Solvents ◽  
Computational Studies ◽  
Computational Results ◽  
Binding Ability ◽  
Protic Solvents ◽  
Aqueous Acidity ◽  
The Eu

AbstractComplexation of a new macrocyclic compound, 2,6-dimethylformamide-calix[4]pyridine (L1), with Eu(III) was studied by spectrophotometry. Stability constants of the Eu(III)/L1complex in different solvents were determined. The results reveal thatL1forms moderately strong complexes with Eu(III) and other lanthanides in aprotic solvents and shows little binding ability with transition metals. Moreover, the binding strength ofL1weakens significantly in protic solvents. Using 2-bromodecanoic acid as the synergistic reagent,L1extracts Am(III) and Eu(III) successfully with a separation factor of SFAm/Eu=1.3, and the distribution ratios of Am(III) and Eu(III) increases as the aqueous acidity is decreased. DFT computational studies were conducted to corroborate the solvent extraction data, and compare the coordination properties of Am(III)/Eu(III) complexes withL1and a related, 2,6-diformamide-calix[4]pyridine (L2). The computational results suggest thatL2could form stable complexes [ML]3+and ML(NO3)3[where M represent Am(III) or Eu(III)] in aqueous phase, in sharp contrast to the case ofL1where such complexes in aqueous phase are not stable.

Experimental and computational study on the aqueous acidity constants of some new aminobenzoic acid compounds

2009 ◽  
Vol 149 (3) ◽  
pp. 60-65 ◽  
Author(s):  
Kamal Alizadeh ◽  
Ali Reza Ghiasvand ◽  
Mohammad Borzoei ◽  
Somaeih Zohrevand ◽  
Behrooz Rezaei ◽  
...  
Keyword(s):  
Computational Study ◽  
Aminobenzoic Acid ◽  
Acidity Constants ◽  
Aqueous Acidity

An Additional Insight into the Correlation between the Distribution Ratios and the Aqueous Acidity of the TODGA System

2007 ◽  
Vol 25 (2) ◽  
pp. 187-204 ◽  
Author(s):  
Yuji Sasaki ◽  
Philippe Rapold ◽  
Makoto Arisaka ◽  
Masaru Hirata ◽  
Takaumi Kimura ◽  
...  
Keyword(s):  
Additional Insight ◽  
Aqueous Acidity ◽  
Insight Into

scholarly journals Cyanex 302: An extractant for Fe3+ from Chloride Medium

1970 ◽  
Vol 46 (4) ◽  
pp. 407-414 ◽  
Author(s):  
MR Ali ◽  
RK Biswas ◽  
SMA Salam ◽  
A Akhter ◽  
AK Karmakar ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Equilibration Time ◽  
Extractant Concentration ◽  
Phase Contact Time ◽  
Extraction Equilibrium ◽  
Cyanex 302 ◽  
Wide Range ◽  
Aqueous Chloride ◽  
Parallel Reactions ◽  
Aqueous Acidity

The solvent extraction of Fe3+ from aqueous chloride solution by bis-(2,4,4-trimethylpentyl) monothiophosphinic acid (Cyanex 302, H2A2) dissolved in kerosene has been investigated over a wide range of aqueous acidity as a function of phase contact time, concentrations of Fe3+, H+ and Cl- in the aqueous phase, Cyanex 302 concentration in the organic phase and temperature. The equilibration time is 50 min. The distribution ratio is found to be independent on [Fe3+] in the aqueous phase at a constant aqueous acidity and extractant concentration. The H+, extractant and Cl- dependences are -1, 0.5 in low concentration region of extractant and -0.5, respectively; which suggest that extraction occurs via the following two parallel reactions: (i) FeCl3 + 0.5 H2A2(o) FeCl2.A(o) + H+ + Cl-; and (ii) FeCl2 + + 0.5 H2A2(o) -----FeCl2A(o) + H+. Temperature dependence data give ΔH value of 9.95 kJ/ mol. The loading capacity of Cyanex 302 towards Fe3+ is 29.41 g Fe3+/100 g Cyanex 302. The extraction equilibrium constant (Kex) is 10-0.632. Extraction ratio is found to be dependent on diluent used. Stripping of the extracted complex is found to be a difficult task, but may be made effective by a solution containing 6 M H2SO4 and 1 M Na2C2O4. Keywords: Extraction equilibrium; Fe3+ extraction; Cyanex 302; Chloride medium.DOI: http://dx.doi.org/10.3329/bjsir.v46i4.9583 BJSIR 2011; 46(4): 407-414

Application of artificial neural networks for predicting the aqueous acidity of various phenols using QSAR

2005 ◽  
Vol 12 (3) ◽  
pp. 338-347 ◽  
Author(s):  
Aziz Habibi-Yangjeh ◽  
Mohammad Danandeh-Jenagharad ◽  
Mahdi Nooshyar
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Artificial Neural ◽  
Aqueous Acidity

Surprisingly Low Aqueous Acidity at the α-Positions of Pyridiniums and Pyrimidinium: The Role of Solvation

2008 ◽  
Vol 10 (13) ◽  
pp. 2757-2760 ◽  
Author(s):  
Freeman M. Wong ◽  
Christina C. Capule ◽  
David X. Chen ◽  
Scott Gronert ◽  
Weiming Wu
Keyword(s):  
Aqueous Acidity

scholarly journals Extraction of Uranium from Aqueous Solution of Nitric Acid and Organic Solvent Using Ionic Liquid

2020 ◽  
Vol 33 (1) ◽  
pp. 43-48
Author(s):  
Pradeep Kumar ◽  
Ashok Khanna
Keyword(s):  
Aqueous Solution ◽  
Ionic Liquid ◽  
Nitric Acid ◽  
Extraction Efficiency ◽  
Local Maximum ◽  
Complexing Agent ◽  
Ftir Studies ◽  
Metallic Cations ◽  
Aqueous Acidity ◽  
Better Than

In present study, tri-n-butylphosphate (TBP), a classical complexing agent for metallic cations, has been studied for the extraction of uranium into ionic liquids (ILs): 1-butyl-3-methylimidazoliumbis( tri-fluoromethylsulfonyl)imide ([BMIM][TF2N]) and trihexyl-tetradecylphosphonium-bis(trifluoromethylsulfonyl) imide ([P(14)666][TF2N]). Increasing HNO3 acidity of aqueous solution from 0.01 to 1 M the distribution ratio, DU decreases from 16 to 1.2 for 1.1 M TBP in [BMIM][TF2N] and the corresponding extraction efficiency (% E) varies from ~94 to 55. In the acidic range of 1 to 8 M DU and % E shows reversal trend of giving a local maximum at 8 M. This behaviour is compared and validates by literature. In contrast, on increasing in aqueous acidity from 0.01 to 8 M the extraction of uranium into [P(14)666][TF2N] ionic liquid, DU enhances from 2 to 39 and (%E) goes up from ~ 51 to 95. Since, [P(14)666][TF2N] works better than [BMIM][TF2N] in the acidic range > 0.1. This ionic liquid has been used for selective separation of uranium from strontium giving a DU of 63 and DSr of 2 with 98% E of uranium at 8 M acidity. To confirm the various species and groups in the formed complex, FTIR studies have been conducted.

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