Excess Thermodynamic and Transport Investigations for the Binary Mixtures of 1,2,3,4-Tetrahydronaphthalene with Fatty Acid Ethyl Esters as Potential Biodiesel Fuels

Experimental investigations of thermophysical properties such as density (ρ), viscosity (η), speed of sound (u), and refractive index (nD) have been carried out for the binary systems of 1,2,3,4-tetrahydronaphthalene (tetralin) with ethyl caprate (EC), ethyl laurate (EL), and ethyl myristate (EM) at temperatures of 293.15–323.15 K and pressure of 0.1 MPa. These measured properties have been employed to calculate various derived parameters such as excess molar volume (VmE), deviation in isentropic compressibility (Δκs), viscosity deviation (Δη), excess Gibbs free energy of activation of viscous flow (ΔG*E), and deviation in refractive index (ΔnD). Further, these parameters have been correlated, employing the Redlich Kister equation. In general, VmE values are negative while Δκs values are positive over the entire composition range of binary mixtures. Compared to the tetralin + EM system, an easy flow of tetralin + EC and tetralin + EL binary mixtures has been ascertained by their negative Δη values. The sign and magnitude of different derived parameters have been used to interpret the existence of specific interactions as well as structural effects within the investigated binary mixtures. Such results could contribute toward the development and designing of bio-based diesel fuels

Structure-making behaviour of L-arginine in aqueous solution of drug ketorolac tromethamine: volumetric, compressibility and viscometric studies

<p>In this work, density <i>ρ</i>, speed of sound <i>u</i> and viscosity <i>η</i>, were measured for L-arginine in aqueous ketorolac tromethamine solutions at various temperatures (293.15, 298.15, 303.15, 308.15 and 313.15 K) and at atmospheric pressure. Apparent molar volume <i>V_Φ</i>, limiting apparent molar volume <i>V°_Φ</i>, limiting apparent molar volume of transfer <i>V°_Φ,tr</i>, limiting molar expansivity <i>E°_Φ</i>, Hepler’s constant <math><mrow><msub><mrow><mrow><mi>∂</mi><mn>2</mn></mrow><msub><mrow><mi>V</mi><mn>0</mn></mrow><mi>Φ</mi></msub><mrow><mo>/</mo></mrow><mi>∂</mi><mrow><mi>T</mi><mn>2</mn></mrow></mrow><mi>P</mi></msub></mrow></math>and hydration number <i>n_H</i> were obtained using density data. Apparent molar isentropic compression <i>K_Φ,S</i>, limiting apparent molar isentropic compression <i>K°_Φ,S</i>, limiting apparent molar isentropic compression of transfer <i>K°_Φ,S,tr</i> and hydration number <i>n_H</i> were obtained using speed of sound data. Jones–Dole coefficient-B <i>B</i>, viscosity B-coefficients of transfer <i>B_tr</i>, variation of <i>B</i> with temperature (<math><mi>d</mi><mi>B</mi><mrow><mo>/</mo></mrow><mi>d</mi><mi>T</mi></math>), free energy of activation of viscous flow per mole of solvent <i>Δμ°^#₂</i> and per mole of solute <i>Δμ°^#₁</i> were obtained from viscosity data. The obtained results are discussed in terms of solute–solvent interactions in these systems.</p