Temperature Dependence of the Electric Conductivity of a Triethylamine/Water Mixture of Critical Composition

Abstract

AbstractResults of measurements of the temperature dependence of the specific conductivity of a triethylamine (TEA)/water mixture of critical composition (xc(TEA) = 0.0777; mole fraction of TEA) as well as of mixtures of non‐critical composition are reported. They are analysed by fitting the function K = a + b · ϵ + c · ϵ2 + d · ϵthetas + e · ϵθ+Δ (ϵ = (Tc,vis – T)/Tc,vis; Tc,vis: visually determined critical temperature; θ: critical exponents; theoretical value Δ = 0.5) to the experimental data. For the analysis the critical exponent θ is fixed at values predicted by different models (θ = 0.65, θ = 0.89). Tc is fixed at the value determined visually for each mixture studied. The analysis of the data shows that in a triethylamine/water mixture of critical composition an anomalous decrease of the electrical conductivity as a function of temperature can be detected as the critical temperature is approached. The reproducibility of the conductivity data is limited by the chemical instability of the system. Therefore it is not possible to decide unequivocally which of the proposed values of the critical exponent Θ is consistent with the data.