Solvent effects on dissociation of substituted benzenesulphonamides in acetone, 1,2-dichloroethane, tetramethylene sulphone, pyridine and some aqueous organic solvent mixtures

1986 ◽  
Vol 51 (9) ◽  
pp. 1948-1957 ◽  
Author(s):  
Miroslav Ludwig ◽  
Oldřich Pytela ◽  
Miroslav Večeřa
Keyword(s):  
Organic Solvent ◽  
General Formula ◽  
Potentiometric Titration ◽  
Solvent Effects ◽  
Dissociation Constants ◽  
Dimethyl Sulphoxide ◽  
Organic Component ◽  
Solvent Mixtures

The potentiometric titration has been used to measure dissociation constants of fifteen substituted arenesulphonamides of general formula XC6H4SO2NH2 (or X2C6H3SO2NH2) in acetone, 1,2-dichloroethane, tetramethylene sulphone, pyridine, and mixtures water-ethanol (25, 50, 75, 90% by vol. of the organic component), water-dimethylformamide (25, 50, 75% by vol.), water-acetone (25% by vol.), and water-2-methoxyethanol (80% by wt.). The results are compared with those published earlier for water, methanol, ethanol, dimethylformamide, dimethyl sulphoxide, and acetonitrile.

Solvent effect in dissociation of substituted benzenesulphonamides in dimethylformamide, dimethyl sulphoxide, and acetonitrile

1984 ◽  
Vol 49 (11) ◽  
pp. 2593-2601 ◽  
Author(s):  
Miroslav Ludwig ◽  
Oldřich Pytela ◽  
Miroslav Večeřa
Keyword(s):  
Factor Analysis ◽  
Solvent Effect ◽  
General Formula ◽  
Potentiometric Titration ◽  
Dissociation Constants ◽  
Dimethyl Sulphoxide ◽  
Short Cycle ◽  
Testing Method

Dissociation constants of fifteen substituted arenesulphonamides of general formula XC6H4.SO2NH2 (or X2C6H3SO2NH2) have been measured by potentiometric titration in dimethylformamide, dimethyl sulphoxide, and acetonitrile. The Hammett substitution correlations have been calculated and interpreted for these media. The pKHA values measured and the results published earlier for methanol, ethanol, and water have been treated by multiple linear regresion using the published set of the parameters characterizing solvents and by factor analysis using the short cycle and the target testing method.

Mathematical representation of apparent dissociation constants in aqueous–organic solvent mixtures

2002 ◽  
Vol 246 (1-2) ◽  
pp. 135-142 ◽  
Author(s):  
Abolghasem Jouyban ◽  
Hak-Kim Chan ◽  
Brian J. Clark ◽  
William E. Acree
Keyword(s):  
Organic Solvent ◽  
Dissociation Constants ◽  
Mathematical Representation ◽  
Solvent Mixtures

Dissociation constants of substituted benzoic acids in water and in organic solvents

1986 ◽  
Vol 51 (10) ◽  
pp. 2135-2142 ◽  
Author(s):  
Miroslav Ludwig ◽  
Václav Baron ◽  
Karel Kalfus ◽  
Oldřich Pytela ◽  
Miroslav Večeřa
Keyword(s):  
Potentiometric Titration ◽  
Organic Solvents ◽  
Solvent Effects ◽  
Dissociation Constants ◽  
Point Of View ◽  
Benzoic Acids ◽  
Hammett Equation ◽  
Substituent Constant ◽  
Reaction Constant ◽  
Substituted Benzoic Acids

Potentiometric titration has been used to measure dissociation constants of 38 monosubstituted benzoic acids in water and in 6 organic solvents (methanol, ethanol, dimethylformamide, acetonitrile, sulfolane, acetone). The results have been analyzed and interpreted from the point of view of substituent and solvent effects on the dissociation of the title substrates. It has been proved that solvents affect not only the reaction constant but also the substituent constant of the Hammett equation.

Further studies an the extended Hammett equation comprising the hydrophobic constant: Reactivity data for benzoic acids, arylacetic acids, β-arylpropionic acids, trans- and cis-cinnamic acids, methyl benzoates; dissociation constants, DDM reaction and alkaline hydrolysis in various water-organic solvent mixtures

1990 ◽  
Vol 55 (1) ◽  
pp. 119-135 ◽  
Author(s):  
Anthonius J. Hoefnagel ◽  
Bartholomeus M. Wepster
Keyword(s):  
Organic Solvent ◽  
Alkaline Hydrolysis ◽  
Dissociation Constants ◽  
Solvent Mixtures ◽  
Benzoic Acids ◽  
Hammett Equation ◽  
Cinnamic Acids ◽  
Tert Butanol ◽  
Arylacetic Acids

The extended Hammett eguaition Δ = ρs + hπ comprising the hydrophobic constant π is found to be effective in the title compounds and reactivities in various solvent mixtures. In 32 vol.% tert-butanol-water hmdecreases in the order ArCOOMe (-0.25), cis-ArCH=CHCOOH (-0.18), ArCOOH and ArCH2COOH (-0.16), ArCH2CH2COOH and trans-ArCH=CHCOOH (-0.07). For ArCOOH, mixtures like 40-60% methanol, 50% ethanol, 50% acetone and 50% dioxane give similar hm values of circa -0.05. For ArCH2COOH the effects of 3-iodo and 4-iodo substituents are acid-weakening in 32% tert-butanol. The consequences of the hπ term for ρ, σ, and the averaging of σ values, are discussed.

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