The importance of the effect of the solvent dielectric constant on ion-pair formation in water at high temperatures and pressures

Previous work on the mechanism of sulphonium salt solvolysis is reviewed briefly. Rate data, determined by two independent methods, is presented for the solvolysis of dimethyl-t-butyl sulphonium iodide, bromide, and chloride in water and various ethanol–water mixtures. Rate dependence on the anion character and concentration of salt is shown to develop as the dielectric constant of the medium is lowered. The results are interpreted in terms of the increasing importance of an ion-pair mechanism as the composition of the medium is changed. The interpretation is substantiated by independent evidence for ion-pair formation.

Download Full-text

Ion pair formation in copper sulfate aqueous solutions at high temperatures

The Journal of Chemical Thermodynamics ◽

10.1016/j.jct.2004.11.003 ◽

2005 ◽

Vol 37 (5) ◽

pp. 499-511 ◽

Cited By ~ 16

Author(s):

Lucila P. Méndez De Leo ◽

Hugo L. Bianchi ◽

Roberto Fernández-Prini

Keyword(s):

Aqueous Solutions ◽

High Temperatures ◽

Copper Sulfate ◽

Ion Pair ◽

Pair Formation ◽

Ion Pair Formation

Download Full-text

A General Equation of the Polarographic Wave Applicable to Solvents of Low Dielectric Constant; Effect of Ion-pair Formation on Half-wave Potentials

Journal of the American Chemical Society ◽

10.1021/ja01493a001 ◽

1960 ◽

Vol 82 (8) ◽

pp. 1837-1841 ◽

Cited By ~ 18

Author(s):

Ward B. Schaap

Keyword(s):

Dielectric Constant ◽

General Equation ◽

Ion Pair ◽

Pair Formation ◽

Low Dielectric Constant ◽

Polarographic Wave ◽

Ion Pair Formation ◽

Low Dielectric ◽

Half Wave

Download Full-text

Tropolone-triethylamine equilibria in various solvents

Australian Journal of Chemistry ◽

10.1071/ch9800491 ◽

1980 ◽

Vol 33 (3) ◽

pp. 491 ◽

Cited By ~ 3

Author(s):

B Poh ◽

H Siow

Keyword(s):

Nuclear Magnetic Resonance ◽

Dielectric Constant ◽

Aprotic Solvent ◽

Ion Pair ◽

Pair Formation ◽

Spectroscopic Methods ◽

Aprotic Solvents ◽

Ion Pair Formation ◽

No Formation ◽

Hydrogen Bonded

Infrared and nuclear magnetic resonance spectroscopic methods were used to study the tropolonetriethylamine equilibria. In aprotic solvents tropolone transfers its proton to triethylamine to form an ion pair which is in equilibrium with the intramolecularly hydrogen-bonded tropolone. The extent of ion pair formation increases with the dielectric constant of the aprotic solvent. Unlike the case of the p- nitrophenol-triethylamine system, there is no formation of a hydrogen bonded complex between tropolone and triethylamine. In the case of the tropolone-dibutylamine system in aprotic solvents, only ion pair formation is observed.

Download Full-text