Solubility hydrocarbons in water

Hermann, R. B. (1971) Theory of hydrophobic bonding. II. The correlation of hydrocarbon solubility in water with solvent cavity surface area. J. Phys. Chem. 76, 2754—2758. 

Figure 9. Effect of methanol on predicted hydrocarbon solubility in water phase ((A) wet hydrocarbon flash (V) wet methanol hydrocarbon flash)...

Soluble in acetone, alcohol, chloroform, ether (Weast, 1986), and many hydrocarbons Solubility in water (25 °C) ... 

In order to achieve some understanding of the nucleation of hydrate crystals from supercooled water + gas systems, it is useful to briefly review the key properties of supercooled water (Section 3.1.1.1), hydrocarbon solubility in water (Section 3.1.1.2), and basic nucleation theory of ice, which can be applied to hydrates (since hydrate nucleation kinetics may be considered analogous, to some extent, to that of ice Section 3.1.1.3). The three subsections of 3.1.1 (i.e., supercooled water, solubility of gas in water, and nucleation) are integral parts of conceptual pictures of nucleation detailed in Section 3.1.2. 

Soluble in many organic solvents (ketones, esters, and aromatic hydrocarbons) solubility in water is 100 g/L insoluble in aliphatic hydrocarbons. Half life at 37°C in phosphate buffer (pH 7.4) is 110 minutes hydrolyzes to 3-hydroxy-1-propanesulfonic acid.1... 

R. B. Hermann, /. Phys. Chem., 76, 2754 (1972). Theory of Hydrophobic Bonding. 2. Correlation of Hydrocarbon Solubility in Water with Solvent Cavity Surface Area. 

The solubility of individual hydrocarbons in pure water at 25 °C, as summarized by Tissot and Welte (1984) is given in Table 3.3. Table 3.3 indicates that there is a marked decrease in solubility with an increase in molecular weight (carbon number) for each class of hydrocarbons (alkanes, cyclo-alkanes, aromatics). It also shows that aromatics are more soluble than alkanes for a given carbon number. Polar heterocompounds (organic acids or alcohols) are more water soluble than the corresponding hydrocarbon with the same carbon number (Tissot and Welte, 1984). The hydrocarbon solubilities in water are influenced by temperature, salinity and pressure. 

Hydrocarbon processing often involves water in the streams, and this can resnlt in the coexistence of two liquid phases and a vapor phase. A valid approach in handling such VLLE conditions is to neglect the hydrocarbon solubility in water, and assume the water phase is pure water. This enables the use of a simplified mixed A -value formulation. 

The usual method of measuring hydrocarbon solubility in water is to ensure equilibrium saturation with an excess of hydrocarbon. If the vapor pressure of an organic compound is known, its solubility can be determined without knowing whether the water is truly saturated. The... 

Furthermore, poor results are obtained for the solubilities and activity coefficients at infinite dilution of alkanes or naphthenes in water. This was accepted by the developers of modified UNIFAC to achieve reliable VLE results, for example, for alcohol/water systems. The reason was that starting from experimental g -values of approx. 250000 for n-hexane in water at room temperature it was not possible to fit alcohol-water parameters which deliver y -values for hexanol in water of 800 and at the same time describe the azeotropic composition of ethanol and higher alcohols with water properly and obtain homogeneous behavior for alcohol-water systems up to C3-alcohols and heterogeneous behavior starting from C4-alcohols. To allow for a prediction of hydrocarbon solubilities in water an empirical relation was developed [61, 62], which allows the estimation of the solubilities of hydrocarbons in water and of water in hydrocarbons (see below). 

Hydrocarbon Solubility in water Xexp Solubility in water Xcaic... 

Table 5.18 Parameters for the empirical estimation of hydrocarbon solubilities in water.

Additives such as GnCl decrease the hydrophobic effect, so they increase the solubility of hydrocarbons in water. They are commonly called "salting in" agents to indicate this. By contrast, ordinary salts such as NaCl decrease hydrocarbon solubility in water, and are "salting out" agents. We have studied both the reasons for this behavior and the general use of these effects to detect hydrophobic contributions to rates and equilibria. Recently we have initiated a program to put the effects on a more quantitative basis. 

Minimum In the temperature dependency of hydrocarbon solubility In water... 

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