Proton magnetic resonance investigations of alkylammonium carboxylate micelles in nonaqueous solvents. VI. Aggregation of hexylammonium propionate in dimethyl sulfoxide-benzene and dimethyl sulfoxide-water mixed solvent systems

1975 ◽  
Vol 79 (9) ◽  
pp. 917-926 ◽  
Author(s):  
E. J. Fendler ◽  
V. G. Constien ◽  
J. H. Fendler
Keyword(s):  
Magnetic Resonance ◽  
Dimethyl Sulfoxide ◽  
Proton Magnetic Resonance ◽  
Mixed Solvent ◽  
Nonaqueous Solvents ◽  
Solvent Systems

Solvent effects in ultraviolet spectral studies of hydrogen bonding between phenol and N,N-dimethylacetamide

1967 ◽  
Vol 45 (18) ◽  
pp. 2033-2038 ◽  
Author(s):  
F. Takahashi ◽  
W. J. Karoly ◽  
J. B. Greenshields ◽  
N. C. Li
Keyword(s):  
Hydrogen Bonding ◽  
Magnetic Resonance ◽  
Complex Formation ◽  
Equilibrium Constant ◽  
Proton Magnetic Resonance ◽  
Mixed Solvent ◽  
Resonance Method ◽  
Spectral Studies ◽  
Magnetic Resonance Method ◽  
Hydrogen Bonded

Ultraviolet spectral studies of hydrogen bonding between phenol and N,N-dimethylacetamide (DMA) in several media are reported. The equilibrium constant for the formation of the phenol–DMA complex is strongly solvent dependent, varying from 295 1/mole in cyclohexane to 130 in CCl4 and 16 in CHCl3, all at 28°. The greatly reduced value in CHCl3 indicates that the measured equilibrium constant is only an apparent one which does not take into account the decrease in free DMA concentration resulting from hydrogen-bonded complex formation with the solvent acting as hydrogen donor. In CCl4/CHCl3 mixed solvent, in the range of [chloroform] = 0 to 1.227 M, the measured equilibrium constant, K′, varies linearly with K′ [chloroform]. The slope of the line corresponds to the equilibrium constant for the formation of the hydrogen-bonded complex between CHCl3 and DMA in CCl4. The value, 0.9 1/mole, agrees with that obtained from a proton magnetic resonance method. The agreement is particularly noteworthy when we consider that the concentrations of phenol used in the proton magnetic resonance and ultraviolet spectral methods differ by a factor of 200, which leads definitely to the conclusion that the hydrogen-bonded CHCl3–DMA complex formed is 1:1. In cyclohexane/CHCl3 mixed solvent, similar results are obtained.

Solute–solvent effects in the dissociation of thymolsulfonephthalein (an uncharged acid) in aqueous mixtures of acetonitrile (ACN), urea, and dimethyl sulfoxide (DMSO)

1986 ◽  
Vol 64 (8) ◽  
pp. 1521-1526 ◽  
Author(s):  
A. L. De ◽  
A. K. Atta
Keyword(s):  
Solvent Effect ◽  
Dimethyl Sulfoxide ◽  
Solvent Effects ◽  
Mixed Solvent ◽  
Dissociation Constants ◽  
Aqueous Mixtures ◽  
Solvent Interactions ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer ◽  
Solvent Systems

The thermodynamic first dissociation constants, [Formula: see text] of thymolsulfonephthalein (H2A), an uncharged acid, have been determined at 25 °C in aqueous mixtures of 10, 30, 50, 70, and 80 wt% acetonitrile (ACN), 11.52, 20.31, 29.64, and 36.83 wt% urea, 20, 40, 60, and 80 wt% dimethyl sulfoxide (DMSO) by spectrophotometric measurements. The solvent effect represented by ∂(ΔG0) = 2.303RT[p(sK)N − p(wK)N] is found to increase in ACN + H2O system as mol% ACN increases in the solvent. In contrast, the corresponding values in urea + H2O as well as DMSO + H2O solvent systems decrease with increase in proportion of organic component in the solvent, the decrease being sharp in urea + H2O. The results have been discussed in terms of the standard Gibbs energies of transfer of H+ from water to the mixed solvent, [Formula: see text] and the relative values of the standard Gibbs energies of transfer of HA−, [Formula: see text] and of [Formula: see text] in all the solvent systems. The overall dissociation behaviour of the acid (H2A) is found to be dictated by the specific solute-solvent interactions of the species participating in the dissociation equilibria.

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