Dielectric properties for the binary mixture of dimethylsuphoxide and dimethylacetamide with 2-nitrotoluene at microwave frequencies

摘要

The dielectric properties of various organic solvents and binary solvent mixtures at different temperatures over the frequency range of 10 MHz-20 GHz, are investigated using the time domain reflectometry technique, at various temperatures from 15 to 45degreesC. These solvent mixtures-dimethylacetamide-2-nitrotoluene and dimethylsulphoxide-2-nitrotoluene as well as pure solvents display a Debye type dispersion. Their frequency-dependent dielectric properties can be summarized by the three parameters in the Debye equation: a static permittivity, permittivity at high frequency and a dielectric relaxation time constant. The free energy of activation for dipolar relaxation process and the Kirkwood correlation factor were determined using these fitting parameters, for these solvent systems at various temperatures. By using these dielectric parameters, the excess permittivity and excess inverse relaxation time is obtained. The static permittivity increases with increase in volume percentage of 2-nitrotoluene in dimethylacetamide as well as dimethylsulphoxide whereas the relaxation time decreases for both the systems. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 35]