Dielectric properties of dimethyl ether+ethanol liquid mixture at 293.2 K

The dielectric spectra of dimethyl ether (DME) + ethanol liquid mixture were measured at 293.2 K in the frequency range of 0.5-8.5 GHz. The dielectric spectra were correlated with single-phase Debye equation, and the static dielectric constants and the relaxation times for DME+ethanol mixtures were determined. These dielectric properties decreased with increasing DME concentration. The effective averaged angular Kirkwood correlation factors of DME+ethanol mixtures were calculated from the static dielectric constants. The concentration dependence of Kirkwood correlation factors showed concave shapes and has a minimum around 40 mol% of DME. This indicates that the hydrogen bonding between ethanol molecules is weakened with increasing DME composition in ethanol-rich region. In DME-rich region, on the other hand, dipolar orientation between DME molecules plays a dominant role of molecular orientation of DME + ethanol mixture.