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The metastable zone widths (MZWs) of triethanolamine hydrochloride ([HTEA]Cl), defined as the maximum temperature difference ΔTmaxa solution can withstand before crystallization of a solid phase, in water, ethanol−water, and HCl−water mixed solvents have been determined at a saturation temperature T0range from 293.15 to 303.15 K with cooling rate Rfrom 3 to 8 K·h−1. Solubilities of [HTEA]Cl in ethanol−water mixtures have also been obtained using a dynamic method. An equation of MZW with similar form to Sangwal’s equation was derived from the fundamental driving force of crystallization based on chemical potential. With the newly obtained equation, the experimental values of MZW ΔTmaxfor [HTEA]Cl−water system at 298.15 K was correlated with the cooling rate Rby ln(ΔTmax/T0) = −6.140 + 1.222 ln R. The enthalpy of mixing ΔHmixwas calculated with the solubility data, and the result of differential scanning calorimetry (DSC). For [HTEA]Cl−water system, the value of −ΔHmixwas determined to be 30.88 kJ·mol−1, and the addition of both HCl and ethanol led to a decrease of −ΔHmix. The experimental results also showed that MZW could be greatly enhanced when ethanol and HCl were added. It was found that the values of MZW decrease with −ΔHmixfor both [HTEA]Cl−ethanol−water and [HTEA]Cl−HCl−water systems at the same saturation temperature and cooling rate. [ABSTRACT FROM AUTHOR]

[60]Fullerene has zero solubility in water and very low solubility in many organic solvents. It was found that it forms reverse micelles in organic solvents in the presence of nonionic surfactants. Reverse micellization studies of fullerene solutions in the presence of a nonionic surfactant (Span60) were carried out, and the thermodynamic quantities of the reverse micellization process derived from experimental results indicate that the process is spontaneous. The solution behavior of the [60]fullerene was understood from its ability to form microemulsions from its toluene solution and water using different nonionic surfactants. Light scattering studies showed that the dimensions of these microemulsions reach a maximum of 170 nm. Phase behavior at different temperatures indicates the very high surface active nature of [60]fullerene. [ABSTRACT FROM AUTHOR]

Using a laser monitoring technique, the solubility data of taurine in water and aqueous solutions of methanol, ethanol, and 2-propanol were measured over the temperature range from (274.05 to 353.05) K. From the experimental data, the solubility data of taurine in the mixtures of water methanol, water ethanol, and water 2-propanol were found to increase with increasing temperature and decrease with increasing concentration of methanol, ethanol, and 2-propanol in aqueous solution. Also, the water ethanol solution was a better solvent for the purification of taurine. The Apelblat equation, the simplified model of ideal solution, and the λhequation were used to correlate the solubility data; the results showed that the three models mentioned above agreed well with the experimental data, and the Apelblat equation was the most accurate of all of these for these systems. [ABSTRACT FROM AUTHOR]

The nature of the rate enhancements caused by gradually increasing the mole traction of water in the solvent (from 0 to 1) for the cycloaddition reactions of pyridazinium-dicyanomethanide 1,3-dipole, 2, with the dipolarophiles ethyl vinyl ketone (a water-super dipolarophile) and methyl acrylate (a water-normal dipolarophile) in the organic solvents acetonitrile, acetone, methanol, ethanol, and tert-butyl alcohol at 37 °C are explored. In each case as the mole fraction of water surpassed ca. 0.9, exponential rate enhancements were triggered. When methanol replaced water, the rate enhancements were smaller, and no triggering effect was observed. The dramatic rate enhancement triggered for the water-super dipolarophile was significantly reduced as the temperature was raised in the range 29-64 °C. The results suggest that a dominant hydrogen-bonding effect operates in water-induced rate enhancements of 1 ,3-dipolar cycloaddition reactions with water-super dipolarophiles as well as the hydrophobic effect. The hydrogen- bonding effect involves secondary bridging hydrogen bonding from the primary water-solvation shell of the transition state and the growth of structured water clusters. Theoretical calculations strongly support these conclusions. [ABSTRACT FROM AUTHOR]

The article focuses on the significance of mechanistic differences between the transfers of hydrophilic and hydrophobic ions to low-polarity solvents. It differentiates hydrophobic ions and hydrophilic ions capability of transferring water to organic solvents. Furthermore, it emphasizes the significance of the amount of hydrophilic ions in its ability to increase water concentration in organic phase.