The ethane-1,2-diol–2-methoxyethanol solvent system

Abstract

Dissociation constants of 2,4,6-trinitrophenol (picric acid) in a series of ethane-1,2-diol–2-methoxyethanol mixtures have been determined by the conductance method in the temperature range from –10 to 80 °C. The dissociation constants exhibit different variations with temperature in different solvent systems, but they are well fitted by identical equations of the type In K= a₀+a₁T+a₂/T+a₃ In T, from which thermodynamic functions data were also evaluated and discussed. With regard to solvent systems in which a K_max value is observed [i.e. for the solvent mixtures having X(ethane-1,2-diol) > 0.2677], the correlations between K and T obtained from fitting the equation above by Harned's theory and by a pKvs. 1/ε graph, gave results consistent with each other.