Determination of the Protonation Constants of Some 4-(Substituted benzylamino)-4,5-dihydro- 1H-1,2,4-triazol-5-ones by the Potentiometric Method in Ethanol–Water Mixtures

摘要: To gain more information about the effect of solvent on 4,5-dihydro-1H-1,2,4-triazol-5-ones, stoichiometric protonation constants thirteen triazoles in ethanol–water mixtures were determined at an ionic strength 0.10MNaCl and 25.0±0.1 °C under nitrogen atmosphere. A potentiometric method was used the  calculation carried out using PKAS computer program. The correspondingpKa values these mixtures. Thus, effects molecular structure upon acidity investigated. logarithm title 4,5-dihydro- 1H-1,2,4-triazol-5-ones decreased linearly with increasing ethanol content, but 80% did not follow this linear trend. variation is discussed basis specific solute–solvent  interactions. KEYWORDS : Potentiometry, constants, effect, triazoles.