Collect. Czech. Chem. Commun. 1986, 51, 2135-2142

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

Miroslav Ludwig, Václav Baron, Karel Kalfus, Oldřich Pytela and Miroslav Večeřa

Department of Organic Chemistry, Institute of Chemical Technology, 532 10 Pardubice


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.