Ultrasonic Speed and Related Thermo-acoustical Parameters of Solutions of 1,1′-Bis(3-methyl-4-ethoxyacetylphenoxy)cyclohexane at Four Different Temperatures

Abstract

The density (q), viscosity (g) and ultrasonic speed (U) of the pure solvents: 1,4-dioxane (DO), ethyl acetate (EA), tetrahydrofuran (THF) and solutions of the biologically active 1,1 0 -bis(3-methyl-4-ethoxyacetylphenoxy)cyclohexane were investigated at four temperatures: 298, 303, 308 and 313 K over a wide range of concentrations (0.1-0.01 molÁdm -3 ) to understand molecular interactions in these solutions. Various acoustical and thermodynamic parameters such as specific acoustical impedance (Z), isentropic (adiabatic) compressibility (j S ), Rao's molar sound function (R m ), van der Waals constant (b), internal pressure (p), free volume (V f ), intermolecular free path length (L f ), classical absorption coefficient {(a/f 2 ) Cl }, viscous relaxation time (s), Gibbs energy of activation (DG*), enthalpy of activation (DH*) and entropy of activation (DS*) were determined using the q, g and U data. A good to excellent correlation between a given parameter and concentration (C) is observed at all temperatures (T) and solvent systems studied. A linear increase or decrease of acoustical and thermodynamic parameters with concentration and temperature indicate the presence of strong molecular interactions in the solutions. DG* decreases linearly with increasing concentration and temperature in the DO system, while it decreases with C and increases with temperature in the EA and THF systems. The enthalpy of activation (DH*) was found to be practically independent of concentration but DH* and DS* were found to be slightly concentration dependent. In the DO system they are positive, while in the EA and THF systems they are negative.

Fundamental Equation of State for Fluid Tetrahydrofuran

“…Several other authors [ 148 , 156 , 179 ] used the same vibrating-tube apparatus and obtained consistent results with the measurements of Vercher et al [ 198 ]. The main contributor to the uncertainty estimate of these apparatuses is the recommended value of at least 0.03 from Prokopová et al [ 202 ] that was applied to the data of Dhaduk et al [ 148 ], Ivanov [ 156 ], and Piñeiro et al [ 179 ].…”

Volumetric behaviour of tetra-n-butyl ammonium bromide in various solvents at different temperatures

“…Similar results have been reported by other workers [52]. Thus, increase in the internal pressure and decrease of free volume indicate increase the cohesive forces in the solution [53]. The increase in temperature has two opposing effects, namely structure formation (intermolecular association) and structure destruction.…”

Density and Viscosity of (Ethyl Acetate + Diethyl Succinate) Mixtures: Experimental Measurements and Molecular Dynamics Simulations

“…Relative deviations of the experimental viscosity data with the calculated results from the Tait–Andrade model for ETA as a function of the temperature (left panel) and pressure (right panel). Brown triangles, Djojoputro and Ismadji; green triangles, Aminabhavi et al; red circles, Aminabhavi et al; blue squares, Pal and Kumar; blue triangles, Sastry et al; green triangles, Dhaduk et al; □, this work.…”

“…Available literature data on the viscosity of ETA and DES are compared with the Tait–Andrade models, as shown in Figures and . Djojoputro and Ismadji, Aminabhavi et al, , Pal and Kumar, Sastry et al, and Dhaduk et al only experimental studied the liquid viscosity of ETA under atmospheric pressure. Among them, the ETA data from Djojoputro and DES data from Ismadji and Aminabhavi et al generally indicated a temperature-related deviation trend but still fell in a reasonable range (2%).…”

“…The averaged running integrals were fit to the double-exponential function for the period up to the cutoff time with a weighting function. More details can be found in refs − .…”