Refractometry of Water–Ethanol Solutions near Their Contraction Point

Abstract

The concentration dependences of the refractive index in aqueous ethanol solutions at equilibrium have been studied experimentally. Special attention was paid to their behavior in a vicinity of the peculiar point defined as the intersection point of the concentration dependences of the contraction measured at different temperatures or as a point, at which the intensity of molecular light scattering has a maximum. The refractive index is found to noticeably deviate from its reference values in a vicinity of the peculiar point, 0.05 < < 0.1 (is the mole fraction of ethanol). This effect reflects the fact that the equilibrium properties of the solutions concerned are established only during a few weeks. Arguments that the system becomes microinhomogeneous in this concentration interval are presented. K e y w o r d s: water-alcohol solutions, refractive index, microinhomogeneous structure.

Different Structural States of 4-Methylpyridine--Water Solutions: Experimental Study of the Adiabatic Compressibility at the Hypersonic Frequency

“…The extrapolation of the position of the minimum of 𝛽 𝑆 (𝑥) to pure water (𝑥 = 0) predicts the presence of some "critical" temperature 𝑡 ≈ 48 ∘ С in water. This temperature is in good agreement with the results of works [8,9], where, on the base of comparative analysis of the temperature dependences of the shear viscosities of water and argon, the au-ISSN 2071-0194. Ukr.…”

Negative Dispersion of High-Frequency Sound Velocity in Aqueous Solutions of Non-Electrolyte in a Vicinity of the Singular Point Concentration

“…Note another structural feature of the solutions under study and its relationship to the propagation of high-frequency sound. It is known that water molecules can form a 3D network of hydrogen bonds with a coordination close to tetrahedral (see, for example, [7][8][9][10]). The incorporation of nonelectrolyte molecules into the network structure can lead to its stabilization (hardening) in a certain concentration range.…”

Адіабатична Стисливість Водних Розчинів Поліолів

“…The solutions were prepared from doubly distilled water and various polyols of the chemically pure grade. The weighing was performed on an analytical balance with an error of ±2 × 10 −4 g. Solutions of the following polyols and with the following concentrations were studied: erythritol (1,5,15,25,30, and 35 wt.%), xylitol (5,10,20,30,40,50, and 60 wt.%), sorbitol (5,10,20,30,40,60, and 70 wt.%), and mannitol (1,3,10,15, and 20 wt.%).…”

“…The properties of liquid systems in the vicinity of their singular points are researched using various methods [15][16][17][18][19][20], in particular, acoustic spectroscopy [21][22][23].…”