Dielectric dispersion in 1,2-diaminopropane–dimethylaminoethanol mixtures as a function of composition and temperature

Abstract

The dielectric dispersion e' and dielectric loss e of binary mixture of 1,2-diaminopropane–dimethylaminoethanol were measured by employing the time domain reflectometry technique over a frequency range from 10 MHz to 20 GHz at 288, 298, 308, and 318 K temperatures. The accuracy in the measurement of the e' and e values obtained from this technique is within ±5%. To evaluate various dielectric parameters, the frequency dependents complex permittivity (e*(ω) = e' – ie) data, viz., static permittivity e0, relaxation time τ, and permittivity at high frequency e∞ were fitted by the nonlinear least-squares fit method to Debye expression. Temperature dependent e0, τ, Kirkwood correlation factor g, free energy of activation ΔG, and enthalpy of activation ΔH have been determined and discussed in terms of the effect of –NH2 and –CH3 side-group on molecular dynamics and intermolecular hydrogen bonds. The dielectric behaviour of 1,2-diaminopropane and dimethylaminoethanol liquid molecules and their conformations as well as molecular dynamics of the system can be explored only by comparing the dielectric data of the mixture system with the dielectric data of the individual molecules and their dynamics.