Physico-chemical and spectroscopic investigation of flavonoid dispersed C n TAB micelles

In this study, kaempferol (0.2 m/mmol kg −1 ) dispersed cationic surfactant micelles were prepared as a function of alkyltrimethylammonium bromide (C n TAB) hydrophobicity (C = 12 to C = 16). The dispersion study of kaempferol in different C n TAB, i.e. dodecyltrimethylammonium bromide (C = 12), tetradecyltrimethylammonium bromide (C = 14) and hexadecyltrimethylammonium bromide (C = 16), was conducted with the physico-chemical properties of density, sound velocity, viscosity, surface tension, isentropic compressibility, acoustic impedance, surface excess concentration and area occupied per molecule and thermodynamic parameters Gibbs free energy, enthalpy and activation energy measured at 298.15 K. These properties were measured with varying concentration of C n TAB from 0.0260 to 0.0305 mol kg −1 in a 10% (w/w) aqueous dimethyl sulfoxide solvent system. The variations in these measured properties have been used to infer the kaempferol dispersion stability via hydrophobic–hydrophilic, hydrophilic–hydrophilic, van der Waals, hydrogen bonding and other non-covalent interactions.

Deep eutectic solvents for antiepileptic drug phenytoin solubilization: thermodynamic study

Thermodynamic investigations provide information about the solute-solvent interactions in the selection of the proper solvent for different fields of pharmaceutical sciences. Especially, the study of antiepileptic drugs in solutions (ethanol/co-solvent) has been a subject of interest owing to their effect in the systems using interaction with a number of important biological membranes. This work focuses on the measurement of density and speed of sound of the phenytoin (PTH) in ethanol/deep eutectic solvents (choline chloride:ethylene glycol, and choline chloride:glycerol) solutions as the innovative class of green solvents at temperature range (288.15 to 318.15) K. It was determined Hansen solubility parameters for assessment of PTH interactions in the solvent media. Some thermophysical parameters including apparent molar volumes Vϕ, apparent molar isobaric expansion $$E_\varphi^0$$ E φ 0 , and Hepler’s constant, apparent molar isentropic compressibility κφ were obtained and calculated using these data. To correlate the Vϕ and κφ values, the Redlich-Meyer equation was used to calculate the number of quantities containing standard partial molar volume and partial molar isentropic compressibility. Finally, $$\Delta \delta$$ Δ δ values showed a strong interaction between PTH and solvent (ethanol/DES (ChCl:EG)). The thermodynamic analysis of the studied system also plays a crucial role in the pharmaceutical industry.

Thermo Acoustic Study of Salicylaldehyde in Carbon Tetra Chloride at 303.15K, 308.15K, 313.15K

Thermo-acoustic study in binary mixture of salicylaldehyde and carbon tetra chloride were reported at 303.15K, 308.15K, 313.15K. The molecular interaction have been carried out by computing various thermo acoustical parameters i.e. Intermolecular free length (Lf), Specific acoustic Impedance (Z), Molar Volume (Vm), Available Volume (Va), Isentropic compressibility (S) and other constant and the excess value of foresaid parameters have been evaluated by using ultrasonic velocity, density, viscosity data, the results of these parameters conclude the strength of molecular interaction. Keywords: Excess values of Salicylaldehyde, Acoustic Parameters, Molecular Interaction.

Density, Ultrasonic Velocity, Isentropic Compressibility, Molar Volumes and Related Excess Parameters Studies on Ethyl Acetate with 1-Ethanol at 303K, 308K, and 313K

A binary liquid mixture that consists of ethyl acetate and 1-ethanol has been prepared at various concentrations by the mole fraction method. The ultrasonic velocity and density have been determined at 303K, 308K and 313K. From the experimental data, the excess isentropic compressibility, excess molar volumes, excess internal pressures, and excess molar enthalpy have been computed. The variations were observed as polynomial and fitted to the Redlich-Kister polynomial functions. By using this function, adjustable parameters and the standard deviations have been calculated. The experimental and theoretical data reveal that the existence of the intermolecular interactions between the selected liquid system. The partial molar compressibility’s and partial molar volume also calculated at infinite dilution of the system. In general, the intermolecular forces have tended to the variations in the magnitude and sign of the excess parameters. The excess molar volume (Vme), excess isentropic compressibility (), excess internal pressure ( ) and the enthalpy ( ) show the negative magnitude at the entire range of concentrations and temperatures. The significant variations of these parameters with the mole fraction of ethyl acetate have been analysed. Furthermore, the strength of the intermolecular interactions decreased with increasing the experimental temperatures as 303K > 308K >313K.

Study of Acoustical and Physico-chemical Properties for the Ternary Mixture of (Toluene+ Chlorobenzene + Cyclohexane) at 298.15 K Temperature

Ultrasonic velocity (U), density (ρ) for the ternary mixture of (Toluene + Chlorobenzene + Cyclohexane) in the various range of composition has been carried out at 298.15K. The observed data have been utilized to calculate various acoustical parameters like Isentropic compressibility (KS), Intermolecular free length (Lf) and acoustic impedance (Z). The various excess properties like excess ultrasonic velocity(UE ), excess acoustic impedance (ZE ), excess Isentropic compressibility (KS E ) and excess Inter molecular free length (Lf E ) have been calculated and using standard relations to the Redlich-Kister equation. The trend of acoustical and physicochemical parameters confirm the dynamics of molecules at temperature and the magnitude of intermolecular interactions among the constituents of the mixture always reflects the nature of substance. The variations in sign and values of these parameters are help us to know the interaction between component molecules and structural arrangement of the liquid mixture.

Solvodynamic study on Solubility Enhanced Lovastatin in presence of Arginine as Cosolute

In this study, the solute-cosolute interaction, solute-solvent interaction involved in the solubilisation process of ARG solutions and LVS-ARG solution systems are illustrated. The sound velocity values of both solution systems were determined at varying concentrations of ARG (0.01-0.8 mol.dm-3) at 298.15 K. Next, the refractive index and the density of the solution systems was measured at temperature range from 298.15 to 313.15K. Acoustic and volumetric parameters such as isentropic compressibility (KS), apparent isentropic molar compressibility (KSΦ), relative association (RA), acoustic impedance (Z), internal pressure (πi), free volume (Vf), molar volume (Φv0), molar expansibility (ΦE0) were calculated from sound velocity and density data. From the study, an increasing trend in sound velocity was observed with the increase in ARG concentration while compressibility values showed opposite trend. Additionally, solute-solvent interaction and structural effects of water for ARG and LVS-ARG systems are discussed regarding the changes in acoustic parameters.

Estimation of Isentropic Compressibility of Biodiesel Using ELM Strategy: Application in Biofuel Production Processes

Isentropic compressibility is one of the significant properties of biofuel. On the other hand, the complexity related to the experimental procedure makes the detection process of this parameter time-consuming and hard. Thus, we propose a new Machine Learning (ML) method based on Extreme Learning Machine (ELM) to model this important value. A real database containing 483 actual datasets is compared with the outputs predicted by the ELM model. The results of this comparison show that this ML method, with a mean relative error of 0.19 and R 2 values of 1, has a great performance in calculations related to the biodiesel field. In addition, sensitivity analysis exhibits that the most efficient parameter of input variables is the normal melting point to determine isentropic compressibility.

Thermo Acoustic Parameters of Tetrabutylammonium Borate and Perchlorate in Non-Aqueous Solvents

Interactions of electrolytes in a binary mixture can be determined by various techniques. Ultrasonic velocity measurements prove to be one of the important tools for measuring various acoustic properties at variable temperature. Thermo acoustic parameters like Isentropic compressibility (κs),Acoustic impedance (Z), Free volume (Vf), Absorption coefficient (Abscoeff), Intermolecular free length (Lf), Gibb’s free energy (ΔG), Relaxation time (τ), Rao’s constant (Rm), Internal pressure (πi), Wada’s constant (w), and Entropy (H) for Tetrabutylammonium tetraphenylborate (Bu4NBPh4) and Tetrabuty lammonium perchlorate (Bu4NClO4) was calculated using experimental ultrasonic velocities, viscosities and densities at three different temperatures (298K, 308 K and 318K) and 1 atmospheric pressure in non-aqueous solvents like Dimethylsulfoxide (DMSO), Pyridine (Py) and their binary mixtures at 0, 20, 40, 60, 80 and 100 mol% of Py at variable temperatures ranging from 298K to 318K. Both Bu4NBPh4, Bu4NClO4, showed an increase in the ultrasonic velocity values at all the temperatures. This shows that molecular interactions are taking place in both the electrolytes. These increases in the molecular interactions with increase in the concentration of electrolytes in the solvent mixture were discussed in terms of solvent structural effects. And results showed the greater molecular interaction in DMSO rich regions.

Study of nitrazepam drug interaction with alcohol: An ultrasonic and physiochemical investigation

The intermolecular interaction between the constituent components of liquid mixtures can be revealed by ultrasonic analysis. In the present study, interaction of nitrazepam drug with methyl alcohol has been studied and presented using ultrasonic tools. The investigation involves calculation of ultrasonic velocity (ν), density (ρ), viscosity (η) and the associated derived parameters. The specific acoustic impedance (Z), isentropic compressibility(β), relaxation time (τ), intermolecular free length(L_f) and solvation number Sn are calculated to reveal the interaction information. The solvent-solvent and solute-solvent interaction between the nitrazepam and alcohol molecules is considered. To see the impact of nitrazepam drug with alcohol in ordinary day to day scenario, investigation is carried out at normal temperature and pressure conditions with temperature range varying from 303K to 313K range. The results indicate increased molecule association of nitrazepam drug in presence of alcohol. This study suggests the presence of synergistic depressants effect, when nitrazepam drug is used with alcohol.