Equilibria in Acetic Acid: Ion Association Constants of Salts and the Autoprotolysis Constant of Acetic Acid at 105.7°C

1962 ◽  
Vol 15 (3) ◽  
pp. 409 ◽  
Author(s):  
RJL Martin
Keyword(s):  
Acetic Acid ◽  
Perchloric Acid ◽  
Sodium Acetate ◽  
Specific Conductivity ◽  
Ion Pairs ◽  
Sodium Perchlorate ◽  
Ion Association ◽  
Association Constants ◽  
Ion Association Constants

The ion association constants KA=[M+A-]/[M+][A-] which have been measured conductimetrically at 105 7 �C in acetic acid are : perchloric acid 0.0644 X 106, sodium perchlorate 0.1346 x 106, and sodium acetate 0.752 x 106. The parameters 6, centre to centre distance between the ions at contact, which were calculated from Bjerrum's formula, are : perchloric acid 4.52 Ǻ, sodium perchlorate 4.20 Ǻ, and sodium acetate 3.61 Ǻ. The autoprotolysis constant, K = [H2+ Ac][Ac-]= 1.17 x 10-19, was calculated from the specific conductivity of acetic acid at 105.7 �C. The acetic acidium acetate ion pairs were calculated to be 100.0% dissociated.

Octahedral cobalt(III) complexes in dipolar aprotic solvents. II. Association between cis- and trans-dichlorobisethylenediamine cobalt(III) cations,[Co en2 Cl2]+, and chloride and bromide ions in the solvents NN-dimethylformamide, dimethyl sulphoxide, and LVN-dimethylacetamide

1966 ◽  
Vol 19 (1) ◽  
pp. 43 ◽  
Author(s):  
WA Millen ◽  
DW Watts
Keyword(s):  
Spectrophotometric Method ◽  
Ion Pairs ◽  
Ion Association ◽  
Ion Pair ◽  
Association Constants ◽  
Dimethyl Sulphoxide ◽  
Aprotic Solvents ◽  
Ion Association Constants ◽  
Cis And Trans ◽  
Dipolar Aprotic Solvents

Ion association constants at 30� have been determined for the cis-[Co en, Cl2]+Cl- ion pair in NN-dimethylformamide (DMF), NN-dimethylacetamide (DMA), and at 20.0�, 25.0�, and 30.0� in dimethyl sulphoxide (DMSO), by a spectrophotometric method. Association constants for the cis-[Co en2 Cl2]+Br- and the trans- [Co en2 Cl2]+Cl- ion pairs have also been determined in DMF at 30�.

EUROPIUM OXALATE ION ASSOCIATION IN WATER

1966 ◽  
Vol 44 (24) ◽  
pp. 3057-3062 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Acetic Acid ◽  
Ionic Strength ◽  
Stability Constant ◽  
Stability Constants ◽  
Aqueous Phase ◽  
Sodium Acetate ◽  
Ion Association ◽  
Sodium Oxalate ◽  
Aqueous Sodium ◽  
Oxalate Ion

The partitioning of radiotracer 152/151Eu between aqueous sodium oxalate (Na2L) solutions and toluene solutions of thenoyltrifluoroacetone (HTTA) has been studied as a function of the oxalate concentration. The pH of the aqueous phase was controlled by means of sodium acetate – acetic acid mixtures and the ionic strength (I) by NaCl or NaClO4.At low ionic strengths (~0.05) and [L] ~10−4 M EuL+ formed, but at I = 0.95 and [L] ~10−3 M EuL2− also formed. Stability constants for the 1:1 and 1:2 (metal:ligand) complexes are reported.The magnitudes of the stepwise stability constant ratios are discussed.

scholarly journals When spectroscopy fails: The measurement of ion pairing

2006 ◽  
Vol 78 (8) ◽  
pp. 1571-1586 ◽  
Author(s):  
Glenn Hefter
Keyword(s):  
Metal Ion ◽  
Chemical Speciation ◽  
Ion Pairs ◽  
Ion Association ◽  
Ion Pair ◽  
Association Constants ◽  
Spectroscopic Techniques ◽  
Association Equilibria ◽  
Solvent Molecules ◽  
Contact Ion Pairs

Spectroscopic techniques such as UV/vis, NMR, and Raman are powerful tools for the investigation of chemical speciation in solution. However, it is not widely recognized that such techniques do not always provide reliable information about ion association equilibria. Specifically, spectroscopic measurements do not in general produce thermodynamically meaningful association constants for non-contact ion pairs, where the ions are separated by one or more solvent molecules. Such systems can only be properly quantified by techniques such as dielectric or ultrasonic relaxation, which can detect all ion-pair types (or equilibria), or by traditional thermodynamic methods, which detect the overall level of association. Various types of quantitative data are presented for metal ion/sulfate systems in aqueous solution that demonstrate the inadequacy of the major spectroscopic techniques for the investigation of systems that involve solvent-separated ion pairs. The implications for ion association equilibria in general are briefly discussed.

scholarly journals OXIDATION OF BENZALDEHYDE BY QUINOXALINIUM DICHROMATE

2016 ◽  
Vol 12 (9) ◽  
pp. 4396-4403 ◽  
Author(s):  
K Anbarasu ◽  
N. GEETHA
Keyword(s):  
Acetic Acid ◽  
Perchloric Acid ◽  
Reaction Rate ◽  
Sodium Perchlorate ◽  
Activation Parameters ◽  
Probable Mechanism ◽  
Water Medium ◽  
First Order ◽  
Rate Of Reaction ◽  
Acetic Acid Water

The kinetics and mechanism of oxidation of benzaldehyde by quinoxalinium dichromate has been studied in the presence of perchloric acid in 70 % acetic acid - water medium. The reaction follows first order with respect to benzaldehyde, quinoxalinium dichromate and fractional order with respect to perchloric acid. There is no effect on the reaction rate with increase in ionic strength of the medium by adding sodium perchlorate. The rate of reaction increases with increase in the percentage of acetic acid. The reaction does not induce the polymerization with acrylonitrile. The rate of reaction decreases with increase in the concentration of manganoussulphate. The thermodynamic and activation parameters have been calculated and a probable mechanism has been proposed.

The role of ion-association in the chromatographic separation of isomeric cationic cobalt(III)-amine complexes on cation-exchange resins, particularly SP-Sephadex

1977 ◽  
Vol 30 (12) ◽  
pp. 2625 ◽  
Author(s):  
GH Searle
Keyword(s):  
Cation Exchange ◽  
Ion Pairs ◽  
Sodium Perchlorate ◽  
Ion Association ◽  
Chromatographic Separations ◽  
Sodium Tartrate ◽  
Cation Resin ◽  
Cation Exchange Resins ◽  
Exchange Resins

Chromatographic separations of a set of closely similar or isomeric cobalt(III) complexes, of the kinds [Co(dien)2]3+, [Co(dien)(medien)]3+ and [Co(medien)2]3+ [dien = diethylenetriamine; medien = 4-methyldiethylenetriamine or 2,2'-methyliminodi(ethylamine)] on SP-Sephadex C-25 and Dowex 50W-X2 cation-exchange resins have been examined with different eluents as sodium salts. The separations obtained appear to be due primarily to differences in the association constants for ion-pairs formed betwen the complex cations and the eluent anions, rather than due to differences in affinities of the free cations for the resins. The strengths of the associations depend on: (1) the availability on the complex cations of appropriately disposed N-H bonds for hydrogen-bonding to oxyanions, and probably on the acidities of these hydrogens (acidity sec-NH > NH2), rather than on polarity of charge distribution, and (2) the basicities of anions, in the order PO43- > SeO32- > (+)-tartrate2- > SO42- > (+)-Sb2(C,4H2O6)22- > Cl- ≈ NO3- > ClO4-. The effects of association with PO43-, SeO32- and (+)-tartrate2- may be so great that complex cations of different charges are not necessarily eluted in the order of their increasing charges. Determinations of charges and polarities (cis/trans) of cationic complexes by chromatographic procedures must therefore be carried out under conditions where association is minimized, as with sodium perchlorate as eluent. Under these conditions, separations are determined largely by cation-resin interactions which are less specific and less discriminating than cation-anion interactions. SP-Sephadex is a particularly sensitive medium for separating different cationic complexes, and tri- sodium orthophosphate and sodium (+)-tartrate are the most effective and generally useful eluents.

scholarly journals Preparation of Some Novel Copper(I) Complexes and their Molar Conductances in Organic Solvents

2009 ◽  
Vol 64 (3-4) ◽  
pp. 269-272 ◽  
Author(s):  
Dip Singh Gill ◽  
Dilbag Rana
Keyword(s):  
Organic Solvents ◽  
Ion Association ◽  
Solvent System ◽  
Molar Conductance ◽  
Association Constants ◽  
Complex Ions ◽  
Ion Association Constants ◽  
Conductance Data ◽  
Strong Electrolytes ◽  
Reference Electrolyte

Abstract Attempts have been made to prepare some novel copper(I) nitrate, sulfate, and perchlorate complexes. Molar conductances of these complexes have been measured in organic solvents like acetonitrile (AN), acetone (AC), methanol (MeOH), N,N-dimethylformamide (DMF), N,Ndimethylacetamide (DMA), and dimethylsulfoxide (DMSO) at 298 K. The molar conductance data have been analyzed to obtain limiting molar conductances (λ0) and ion association constants (KA) of the electrolytes. The results showed that all these complexes are strong electrolytes in all organic solvents. The limiting ionic molar conductances (λo± ) for various ions have been calculated using Bu4NBPh4 as reference electrolyte. The actual radii for copper(I) complex ions are very large and different in different solvents and indicate some solvation effects in each solvent system

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