Joseph Saab

Aqueous solubility (in the range between 298.15 and 338.15 K), vapor pressures (in the range between 10(-5) and 80 Pa) and Henry's law constant of 1,2,3,4-dibenzanthracene and 1,2,5,6-dibenzanthracene.

Aqueous solubility and vapor pressures of 1,2,3,4-dibenzanthracene and 1,2,5,6-dibenzanthracene were determined using dynamic saturation methods. For the two isomers, aqueous solubility is in the range between 10(-10) and 10(-2) in molar fraction corresponding to temperature between 298.15 and 338.15K. Vapor pressures of the pure solutes range from 10(-5) to 80 Pa. Prior to the study of the two dibenzanthracenes and in order to check the experimental procedures, solubility of fluoranthene (between 298 and 338 K) and vapor pressures of phenanthrene and fluoranthene (between 300 and 470 K) were measured. From aqueous solubility data coupled with the vapor pressures of the pure solutes, partition coefficient air-water, KAW, and Henrys constant, KH, of environmental relevance were calculated.

Salting-out phenomenon and 1-octanol/water partition coefficient of metalaxyl pesticide.

In this paper, we present the effect of inorganic cations such as Na+, K+, Ca2+, Mg2+ on the salting-out phenomenon of metalaxyl from pure water to aqueous salt solutions. Moreover the 1-octanol/water partition coefficient in pure water is presented. To accomplish this, aqueous solubility of metalaxyl was determined in pure water, in different salt solution (NaCl, KCl, CaCl2 and MgCl2), and at different concentration level ranging from 0.01 to 1.5 M. The 1-octanol/water partition coefficient was determined using the static shake-flask method. Solubility was determined using dynamic saturation method for pure water in the range of 298.15-325.15 K and at 298.15 K for different salt solutions. The solubility value in pure water for studied interval was found constant (m=3.118×10(-2) mol kg(-1)). Solubility values were used to calculate the standard molar Gibbs free energy of dissolution (ΔsolG°) and transfer (ΔtrG°) at 298.15 K. The values of ΔtrG° from pure to all studied aqueous salt solutions did not exceed 2 kJ mol(-1), the value of ΔsolG° of dissolution is 18.5 ±0.72 kJ mol(-1). The 1-octanol/water partition coefficient in pure water log Ko/w is equal to 1.69. The obtained results confirm the classification of the neutral metalaxyl as a slightly hydrophobic molecule.

Dynamic Fluid Saturation Method for Hydrocarbons Thermodynamics’ Properties Determination

Low solubility compounds suffer from lack of data, leading to an impoverishment in thermodynamic parameters such as Gibbs free energy (ΔG), enthalpy of dissolution (ΔH), entropy (ΔS), infinite dilution coefficient (γ∞ ) and isobaric heat capacity (Cp ) of utmost practical importance for industrial optimization processes. Dynamic fluid method is a novel technique for low solubility (expressed as molar fraction χ) determination based on the saturation of a specific heated fluid passing through a saturation cell. The heated components are kept inside a chromatographic oven maintained at a constant temperature to within ± 0.05°C by means of a PID temperature controller. A regular stream of fluid, using a constant flow pump, passes through the saturation cell packed with an inert stationary phase (Gaz chrom R 60/80) pre-coated with the organic compound. The solute transported by the fluid is subsequently trapped in a specific extraction column (inverse phase). The organic compound is removed by back flushing using the appropriate solvent in order to dissolve and carry out the totality. A low flow of fluid through the generator column is to be set to avoid safely the formation of colloidal dispersion, to increase the contact time and to keep small pressure drops across the generator/extractor column. The gas chromatography coupled to mass spectrometer detector is used in order to quantify the solute. The validation of this apparatus was achieved by comparison of our values with the ones extracted from previous papers using the static method to determine aqueous solubility of the ethylbenzene, and a precision of our solubility measurements was established to be better than 0.2%. In continuous, aqueous solubility and thermodynamics properties of perfluorocarbons compounds were determined in the range of temperature from 273 K to 333 K. Considering the contribution of chromatographic, calibration and other operational errors, the combined measurement uncertainty (standard deviation) was established to be less than 3%.Copyright