Ultrasonic Study of Molecular Interactions and Compressibility Behaviour of Samarium Soaps in Benzene-DMSO Mixture

Ultrasonic measurements of samarium soaps (palmitate and myristate) have been carried out in a mixture of benzene and DMSO (70%-30% v/v) to determine the critical micellar concentration(CMC), soap-solvent interaction and various acoustic parameters. The results show that ultrasonic velocity, intermolecular free length, adiabatic compressibility, adiabatic molar volume and apparent molar compressibility decrease while specific acoustic impedance, relative association and solvation number increase with increase in soap concentration. The results of ultrasonic measurements have also been explained in terms of well-known equations. Keywords: Ultrasonic measurements, molecular interactions, samarium soaps, compressibility, critical micellar concentration(CMC).

Ultrasonic Investigation of Binary Solutions of Petrolium And Its Products

<p>Experiment values of densities and ultrasonic speed of petroleum product Gasoline (Petrol) and 2T Oil were taken in different volume concentrations from 5%, 10%------, and 95% at different temperatures from 298.15K to 318.15K having difference of 5K. From the experimental data, Apparent Molar Compressibility (<em>ϕ_K</em>), Relative Association (<em>R_A</em>), Solvation Number (<em>S_n</em>), Free Energy of Activation (<em>ΔE</em>), Excess Adiabatic Compressibility (<em>β_ad^E</em>), Excess Volume (<em>V^E</em>), Excess Free Length (<em>L_f^E</em>) have been computed. These parameters are used to focus light on the nature of component molecules of binary liquids and the excess functions are found to be sensitive to the nature and extent of the intermolecular interactions taking place in these binary mixtures.</p>

Thermodynamics and acoustic effects of quercetin on micellization and interaction behaviour of CTAB in different hydroethanol solvent systems

Flavonoids amongst the class of secondary metabolites possess numerous health benefits, are known for its use in pharmaceutical industry. Quercetin, a flavonoid has more prominent medical advantages however its utilization is constrained because of various instability and insolubility issues and therefore, taken into consideration for studying its physico-chemical properties. In view of that, the thermodynamic and thermoacoustic properties of quercetin were examined in presence of cationic surfactant cetyltrimethylammonium bromide (CTAB) at different hydroethanolic concentrations and temperatures. The conductivity studies were used to calculate change in enthalpy (∆Hom), change in entropy (∆Som) and change in Gibbs free Energy (∆Gom) of micellization. The interactions between quercetin and CTAB were found to be endothermic, entropically controlled and spontaneous. Further, ultrasonic sound velocity and density studies were carried out and utilized for the calculation of thermoacoustic parameters i.e. apparent molar volume and apparent molar compressibility. Thermoacoustic properties revealed that at higher surfactant concentration, hydrophobic interactions are dominant. The results suggested that the flavonoid-surfactant interactions in hydroethanolic solutions is more favourable as compared with aqueous solution. Overall, the data is favourable for the framework to be used for detailing advancement, drug development, drug industry, pharmaceutical industry, medical administration and formulation development studies.

Acoustical Studies of Ternary Liquid Mixtures of 2-Aminothiazole in DMF-Water at Different Temperatures

The nature and the relative strength of the intermolecular interaction between the components of the liquid mixtures have been successfully investigated by ultrasonic method. In present study, the densities (ρ), ultrasonic velocities (u), viscosity (ɳ) and refractive index (nD) in a ternary liquid mixture of 2-aminothiazole with N,N-dimethylformamide (DMF) in water have been measured at 303.15, 308.15, 313.15,318.15 and 323.15 K respectively, over the entire composition range by using densitometer, ultrasonic interferometer, viscometer and refractmeter respectively. The measured data have been used to compute the various thermo-acoustic parameters using the standard relations namely, adiabatic compressibility (βs), intermolecular free length (Lf), specific acoustic Impedance (Z),Wada constant (W), molar sound velocity (R), relative association (RA), apparent molar compressibility (),apparent molar volume () viscosity relaxation time (Г),absorption coefficient, internal pressure (ᴨ),free volume (Vf),Gibb҆ s free energy (∆G) and specific refraction (r), etc. The results have been analyzed on the basis of variation in thermodynamic parameters. These parameters are useful for explaining the molecular association and interaction between the components of ternary liquid mixtures. The variation in densities and ultrasonic velocities with concentrations in the system show similar trends for evaluated parameters of the constituents in ternary mixture at different temperatures. The results have been interpreted in terms of solute-solvent and solvent-solvent interaction.

Acoustical Behaviour of Sodium Nitroprusside in Aquo-Organic Solvent Media at 308.15 K

Density and ultrasonic velocity have been measured for sodium nitroprusside in aqueous solutions of CH3OH, ethylene glycol, DMSO, and n-propanol solvents at 308.15 K. A quantitative relationship has been established among the acoustical properties like ultrasonic velocity (U), adiabatic compressibility (β), intermolecular free length (Lf), acoustic impedance (Z), apparent molar compressibility (Kϕ), apparent molar volume (Vϕ), limiting apparent molar compressibility (Kϕ0) limiting apparent molar volume (Vϕ0), and their constants (SK,Sv). From the obtained values, molecular interaction study has been made successfully in the light of these acoustical properties through hydrogen bonding in solute and solvent mixture.

Interactions of 6-aminopurine (adenine) in water and aqueous urea solutions

Density (ρ), ultrasonic velocity (U), viscosity (η), and absorbance (A) of adenine in water, 1 M, 3 M, and 6 M aqueous urea solutions have been measured in the presence (and absence) of different concentrations of salts, i.e., NaCl, KCl, and CaCl2. From these measured values, the apparent molar volume (ϕv), experimental slope (Sv), apparent molar compressibility (ϕK), viscosity coefficients A and B of Jones–Dole equation, specific acoustic impedance (Z), hydration number (Sn), internal pressure (Pi), molar absorptivity (ε), hypochromicity (h), and oscillator strength (f) have been calculated at 298.15 K. The increasing and (or) decreasing trends of all these parameters indicate a strong interaction of urea in moderate concentration (1 M and 3 M) with adenine especially at the hydrophilic/polar and ionic sites, particularly by hydrogen bonding. However, the interaction at hydrophobic sites are relatively weaker. Higher concentrations of urea (6 M) have more denaturation effect. The π–π interactions (stacking) in adenine are more prominent in concentrated solutions and are also strengthened by the presence of cations up to an optimum concentration of salts (cut-off point). The self-association of urea and adenine is more significant in concentrated aqueous solutions and becomes negligible on dilution.Key words: interaction, adenine, urea, density, viscosity, and ultrasonic velocity.