The dissociation constant of p-Nitroanilinium ions in water-Sulfolane solvents at 25ºC

Abstract EN

The dissociation constants of p-nitroanilinium ions have been determined in water-sulfolane mixtures at 25ºC using spectrophotometric method.

The p(K)BH+ is found to decrease with progressive addition of sulfolane which indicates that the basicity of the medium is increased by the addition of sulfolane.

The relative basicity of the medium is compared with other water-solvent mixtures and it is found that the basicity decreases in the order of: NMH-H2O > THF-H2O > DMF H2O > ECS-H2O > AN-H2O > Sulfolane H2O > HAc-H2O The acidity function, Ho, of HCl in H2O-sulfolane mixtures is also determined and is found to increase with increase of the organic solvent component for a fixed acid concentration.

This is explained due to the salting in effect, which differs with the organic solvent.

It showed a decrease in the order of: NMF > DMSO > DMF > Dioxan > ECS > EtOH = Acetone > Sulfolane.