Solubility temperature effect

Mills AC, Biggar JW (1969) Solubility-temperature effect on the adsorption of gamma and beta—BHC from aqueous and hexane solutions by soils materials. Soil Sci Am Soc Am Proc 33 210-216... 

Mills, A.C. and J.W. Biggar. Solubility-Temperature Effect on the Adsorption of Gamma-and Beta-BHC from Aqueous and Hexane Solutions by Soil Materials, Soil Sci. Soc. Am. Proa, 33 210-216 (1969). 

In terms of the solubilities of solutes in a supercritical phase, the following generalizations can be made. Solute solubiUties in supercritical fluids approach and sometimes exceed those of Hquid solvents as the SCF density increases. SolubiUties typically increase as the pressure is increased. Increasing the temperature can cause increases, decreases, or no change in solute solubiUties, depending on the temperature effect on solvent density and/or the solute vapor pressure. Also, at constant SCF density, a temperature increase increases the solute solubiUty (16). 

The solubility of the precipitates encountered in quantitative analysis increases with rise of temperature. With some substances the influence of temperature is small, but with others it is quite appreciable. Thus the solubility of silver chloride at 10 and 100 °C is 1.72 and 21.1mgL 1 respectively, whilst that of barium sulphate at these two temperatures is 2.2 and 3.9 mg L 1 respectively. In many instances, the common ion effect reduces the solubility to so.small a value that the temperature effect, which is otherwise appreciable, becomes very small. Wherever possible it is advantageous to filter while the solution is hot the rate of filtration is increased, as is also the solubility of foreign substances, thus rendering their removal from the precipitate more complete. The double phosphates of ammonium with magnesium, manganese or zinc, as well as lead sulphate and silver chloride, are usually filtered at the laboratory temperature to avoid solubility losses. 

Blends of sodium hypochlorite with 15% HC1 and with 12% HCl/3% HF have been used to stimulate aqueous fluid injection wells(143). Waterflood injection wells have also been stimulated by injecting linear alcohol propoxyethoxysulfate salts in the absence of any acid (144). The oil near the well bore is mobilized thus increasing the relative permeability of the rock to water (145). Temperature effects on interfacial tension and on surfactant solubility can be a critical factor in surfactant selection for this application (146). 

The properties of hydroxyethylcellulose are like those of methylcellulose except for the fact that there is little or no temperature effect on solubility. The degree of substitution required to impart water solubility will depend both upon the degree of polymerization of the cellulose and upon the uniformity of substitution. It is of interest... 

The van t Hoff equation also has been used to describe the temperature effect on Henry s law constant over a narrow range for volatile chlorinated organic chemicals (Ashworth et al. 1988) and chlorobenzenes, polychlorinated biphenyls, and polynuclear aromatic hydrocarbons (ten Hulscher et al. 1992, Alaee et al. 1996). Henry s law constant can be expressed as the ratio of vapor pressure to solubility, i.e., pic or plx for dilute solutions. Note that since H is expressed using a volumetric concentration, it is also affected by the effect of temperature on liquid density whereas kH using mole fraction is unaffected by liquid density (Tucker and Christian 1979), thus... 

For most organic chemicals the solubility is reported at a defined temperature in distilled water. For substances which dissociate (e.g., phenols, carboxylic acids and amines) it is essential to report the pH of the determination because the extent of dissociation affects the solubility. It is common to maintain the desired pH by buffering with an appropriate electrolyte mixture. This raises the complication that the presence of electrolytes modifies the water structure and changes the solubility. The effect is usually salting-out. For example, many hydrocarbons have solubilities in seawater about 75% of their solubilities in distilled water. Care must thus be taken to interpret and use reported data properly when electrolytes are present. 

Henry s law constant can be regarded as a ratio of vapor pressure to solubility, thus it is subject to the same effects that electrolytes have on solubility. Temperature affects both properties. Some methods are as follows ... 

Temperature effects on solubility products are readily assessed as most solubility reactions are clearly seen as endothermic and disorder increasing. Raising the temperature will thus increase Ksp together with the solubility of the solid. 

Equation 1 implies that solubility is independent of solvent type, and is only a function of the equilibrium temperature and characteristic properties of the solid phase. In real systems the effect of non-ideality in the liquid phase can significantly impact the solubility. This effect can be correlated using an activity coefficient (y) to account for the non-ideal liquid phase interactions between the dissolved solute and solvent molecules. Eq. 1. then becomes [7,8] ... 

Henry s Law constant (i.e., H, see Sect. 2.1.3) expresses the equilibrium relationship between solution concentration of a PCB isomer and air concentration. This H constant is a major factor used in estimating the loss of PCBs from solid and water phases. Several workers measured H constants for various PCB isomers [411,412]. Burkhard et al. [52] estimated H by calculating the ratio of the vapor pressure of the pure compound to its aqueous solubility (Eq. 13, Sect. 2.1.3). Henry s Law constant is temperature dependent and must be corrected for environmental conditions. The data and estimates presented in Table 7 are for 25 °C. Nicholson et al. [413] outlined procedures for adjusting the constants for temperature effects. 

How can this be No additional gas was added to the water. The answer lies in the nonlinear temperature effect on the Bunsen solubility coefficient (Figure 6.1). Because of the concave nature of the curves relating the Bunsen solubility coefficient to temperature, the result of this type of postequilibration temperature change is always supersaturation. 

Calcium carbonate solubility is also temperature and pressure dependent. Pressure is a 6r more important fector than temperature in influencing solubility. As illustrated in Table 15.1, a 20°C drop in temperature boosts solubility 4%, whereas the pressure increase associated with a 4-km increase in water depth increases solubility 200-fold. The large pressure effect arises from the susceptibility of the fully hydrated divalent Ca and CO ions to electrostriction. Calcite and aragonite are examples of minerals whose solubility increases with decreasing temperature. This unusual behavior is referred to as retrograde solubility. Because of the pressure and temperature effects, calcium carbonate is fer more soluble in the deep sea than in the surfece waters (See the online appendix on the companion website). 

Approximate solubility of the solvent in the aqueous phase Temperature effects... 

Selected entries from Methods in Enzymology [vol, page(s)] Theory, 63, 340-352 measurement, 63, 365 cryosolvent [catalytic effect, 63, 344-346 choice, 63, 341-343 dielectric constant, 63, 354 electrolyte solubility, 63, 355, 356 enzyme stability, 63, 344 pH measurements, 63, 357, 358 preparation, 63, 358-361 viscosity effects, 63, 358] intermediate detection, 63, 349, 350 mixing techniques, 63, 361, 362 rapid reaction techniques, 63, 367-369 temperature control, 63, 363-367 temperature effect on catalysis, 63, 348, 349 temperature effect on enzyme structure, 63, 348. 

Studies on non-ionic surfactants as effective drag-reducing additives have been submitted by Zakin (1972). He studied various effects on three non-ionic surfactants formed from straight-chain alcohols and ethyleneoxide. These surfactants have an upper and a lower temperature limit for solubility in water and prove effective drag reducers near their upper critical solubility temperature or clouding point. The clouding point is the point at which a solution of a non-ionic agent in water becomes turbid as the temperature is raised. 

Temperature Effect. Near the boiling point of water, the solubility—temperature relationship undeigoes an abmpt inversion. Over a narrow temperature range, solutions become cloudy and the polymer precipitates the polymer cannot dissolve in water above this precipitation temperature. In Figure 4, this limit or cloud point is shown as a function of polymer concentration for poly(ethylene oxide) of 2 x 106 molecular weight. 

Nonionic surfactants tend to show the opposite temperature effect As the temperature is raised, a point may be reached at which large aggregates precipitate out into a distinct phase. The temperature at which this happens is referred to as the cloud point. It is usually less sharp than the Krafft temperature.2 The phenomenon that nonionic surfactants become less soluble at elevated temperature will be important when we discuss the phase behavior of emulsions. 

For cosolvent systems, because the heat of solution in different solvent systems is generally different, the temperature effect on solubility in these systems is also different. Detailed solubility mapping in the solvents of interest, including the effect of pH (forionizable compounds), temperature,... 

Caution should be exercised when considering temperature effects on solubilization by micelles, since the aqueous solubility of the solute and thus its micelle/water partition coefLcient can also change in response to temperature changes. For example, it has been reported that although tt solubility of benzoic acid in a series of polyoxyethylene nonionic surfactants increases with temperature, the micelle/water partition coefLci rt, shows a minimum at 2C, presumably due to the increase in the aqueous solubility of benzoic acid (Humphreys and Rhodes, 1968). The increasr in Km with increasing temperature was attributed to an increase in micellar size, as the cloud point temperature of the surfactant is approached (Humphreys and Rhodes, 1968). 

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