The dielectric properties of alcohols–water solutions. I. The alcohol rich region

Abstract

We present here the first results of a systematic study of the dielectric properties of alcohols-water solutions. The complex dielectric constant i = t;' -it;" and the dielectric relaxation time T of MeOH, BtOH, 2-PrOH alcohols, and their aqueous solutions are reported for some values of the water mole fraction Xw in the range 0:::; x. :::; 0.5, at various temperatures (from 30·C down to -43 ·C for MeOH and its solutions). T has been measured by a two coaxial resonators spectrometer in a significant frequency range for the principal relaxation region of these liquids (0.47-4 GHz). Measurements of t;' at \3 MHz with a different experimental apparatus have also been made. Our data do not confirm previous determinations of T vs X. at 30 ·C. In all the investigated temperature range, T is a decreasing monotone function of Xw for the aqueous solutions of BtOH and 2-PrOH. On the contrary, the dielectric relaxation time of MeOH aqueous solution is practically constant up to X. = 0.1 at 30 ·C; at O· and -25 ·C, T increases at the beginning and a maximum is present; at lower temperature, T increases with x •. The observed behavior of T is discussed and a model for the dielectric relaxation in H-bond associated liquids is suggested.(1)

Solvent structure effects on solvated electron reactions with ions in 2-butanol/water mixed solvents

“…Rearrangement of [6] gives the dimensionless ratio of reaction parameters Kr,/rd, which is a sort of reaction efficiency parameter:…”

“…Alcohol/water mixtures are good systems to study the effects of solvent structure on solvated electron reactivity because varying the composition of the mixture results in strong variations in the solvent structure, as reflected in physical properties such as viscosity (5) and dielectric relaxation time (6).…”

ESR Spectroscopy of Nitroxides: Kinetics and Dynamics of Exchange Reactins

“…For comparison, both older and newer works [102][103][104][105] report only a single relaxation process for methanol, resulting in a L which ranges from 4.58 ps to 10.6 ps. The reason that these latter experiments have only detected one relaxation time is, that they have been conducted using a relatively narrow frequency range and thus a long extrapolation for determination of ∞.…”

Dielectric Properties of 1-Hexanol in Mesitylene Solution on Admixture of Aromatic Dihydric Alcohols

“…Binary mixtures of water with alcohols have a t tracted special attention as one can hope to elucidate the effects of self and hetero-association and structure formation in those systems [21][22][23][24][25][26][27][28][29]. In that connec tion also binary mixtures of dihydric and monohydric alcohols are of interest since, to a certain degree, dihy dric alcohols resemble water in their dielectric be haviour [29].…”