GAWRYS, KEITH LOUIS. How Asphaltenes Aggregate: Role of Chemistry and Solvent. (Under the direction of Peter K. Kilpatrick) Asphaltenes from three crude oils were separated on a preparatory-scale into 20 30 discrete subfractions by sequential precipitation from mixtures of n-heptane and toluene. The earliest fractions precipitated were characterized by lower than average aromaticity and atomic ...

The solubility of naproxen in binary mixtures of polyethylene glycol 200 (PEG 200) + water at the temperature range from 298.0 K to 318.0 K were reported. The combinations of Jouyban-Acree model + van't Hoff and Jouyban-Acree model + partial solubility parameters were used to predict the solubility of naproxen in PEG 200 + water mixtures at different temperatures. Combination of Jouyban-Acree m...

The solubility of acetaminophen and ibuprofen in binary and ternary mixtures of N-methyl pyrrolidone, polyethylene glycol 600 and water at 25 °C were determined and the solubilities are mathematically represented by the Jouyban–Acree model. The density of the solute-free solvent mixtures was measured and employed to train the Jouyban–Acree model and then the densities of the saturated solutions...

The complete solution to the mean-spherical approximation is given for an arbitrary mixture of ions in a dipolar solvent. calculation done overall neutral collection charged hard spheres (ions) and dipoles (solvent) that bear central point dipole. Previous solutions this problem were not consistent because they did include solvent particles as (neutral) solute mixture. present accounts peculiar...

A capillary electrophoresis method was used for assay of some degradation products of carvedilol. The optimized parameters were as; running buffer 80 mM acetate dissolved in methanol/ethanol mixture (65:35 v/v), applied voltage of 19 kV, temperature is 20 ºC and the wavelength range of 200-350 nm. The results indicate that the proposed CE method could effectively separate carvedilol from its de...

the molecular associations in the binary mixtures of (methanol/solvent), (ethanol/solvent) and (propanol/solvent) were studied using nmr, ftir and vle data at different temperatures. the activity coefficients as the most important quantities representing the mixture deviation form ideal behavior were evaluated by using various association models to express the physical and chemical contribution...

The paper presents results of the shear viscosity measurements performed on diluted binary mixtures of mesogenic solvent n-hexylcyanobiphenyl (C6H13PhPhC≡N, 6CB) and two non-mesogenic admixtures: (i) n-heptylcyanophenyl (C7H15PhC≡N, 7CP), composed of the molecules of the same polarity as the solvent molecules but of a slightly shorter length, and (ii) 4-n-propylcyclohexyl-4’-n-pentylphenyl (C3H...

A general model has been developed for calculating the static dielectric constant of mixed-solvent electrolyte solutions. For mixtures of solvents without electrolyte components, the model is based on an empirical modification of the Kirkwood theory for multicomponent systems. For systems containing electrolytes, the model takes into account the effects of ions and ion pairs and, therefore, it ...