Nonpolar liquid

The heat of immersion is measured calorimetrically with finely divided powders as described by several authors [9,11-14] and also in Section XVI-4. Some hi data are given in Table X-1. Polar solids show large heats of immersion in polar liquids and smaller ones in nonpolar liquids. Zetdemoyer [15] noted that for a given solid, hi was essentially a linear function of the dipole moment of the wetting liquid. 

It is best applied to nonpolar liquids which form unassociated vapors. 

For predicting liquid diffiisivities of binary nonpolar liquid systems at high solute dilution, Umesi " developed a method that only depends on the viscosity of the solvent (2) and the radius of gyration of the solvent (2) and the solute (1). The Technical Data Book— Petroleum Refining gives the method and values of the radii of gyration for common hydrocarbons. Errors average 16 percent but reach 30 percent at times. 

For concentrated binary nonpolar liquid systems (more than 5 mole percent solute), the diffiisivity can be estimated by a molar average mixing rule developed by Caldwell and Babb, " Eq. (2-156). 

For multiconmonent nonpolar liquid systems, Leffler and Ciil-linan developea a mixing rule, Eq. (2-157). 

The surface tension 7 is a measure of the work required to create unit area of surface from molecules in the bulk it is expressed in ergs per square centimeter or dynes per centimeter. The surface tension is a bulk property, not a molecular property. There appears to be some trend of y with other measures of polarity, but a lower limit of y is reached with very nonpolar liquids this limit (evidently about 15 dyn/cm) reflects the ever-present dispersion force between the molecules of liquid. 

Alternatively, starting with water, the number of dipoles per cubic centimeter may be progressively diminished by diluting the water with a nonpolar liquid, such as dioxane. Values for dioxane-water mixtures... 

If the principal cohesive forces between solute molecules are London forces, then the best solvent is likely to be one that can mimic those forces. For example, a good solvent for nonpolar substances is the nonpolar liquid carbon disulfide, CS2-It is a far better solvent than water for sulfur because solid sulfur is a molecular solid of S8 molecules held together by London forces (Fig. 8.19). The sulfur molecules cannot penetrate into the strongly hydrogen-bonded structure of water, because they cannot replace those bonds with interactions of similar strength. 

The simplest transition metal carbonyls are mononuclear of the type M(CO)x, in other words those with only one metal atom. They are hydrophobic but soluble to some extent in nonpolar liquids, such as n-butane or propane. The dinuclear carbonyls are more complex but have the same general characteristics as the mononuclear carbonyls. The carbonyls, which are or could be used in CVD, are listed in Table 3.4 with some of their properties. 

At the opposite extreme, molecular solids contain individual molecules bound together by various combinations of dispersion forces, dipole forces, and hydrogen bonds. Conforming to like dissolves like, molecular solids dissolve readily in solvents with similar types of intermolecular forces. Nonpolar I2, for instance, is soluble in nonpolar liquids such as carbon tetrachloride (CCI4). Many organic compounds are molecular solids that dissolve in organic liquids such as cyclohexane and acetone. 

The best solvent for a molecular solid Is one whose Intermolecular forces match the forces holding the molecules in the crystal. For a solid held together by dispersion forces, good solvents are nonpolar liquids such as carbon tetrachloride (CCI4) and cyclohexane (Cg H12) For polar solids, a polar solvent such as acetone works well. Example provides some practice in recognizing solubility types. 

Metals do not dissolve in water, because they contain extensive delocalized bonding networks that must be disrupted before the metal can dissolve. A few metals react with water, and several reacf with aqueous acids, but no metal will simply dissolve in water. Likewise, metals do not dissolve in nonpolar liquid solvents. 

Every interface is more or less electrically charged, unless special care is exercised experimentally [26]. The energy of the system containing the interface hence depends on its electrical state. The thermodynamics of interfaces that explicitly takes account of the contribution of the phase-boundary potential is called the thermodynamics of electrocapillarity [27]. Thermodynamic treatments of the electrocapillary phenomena at the electrode solution interface have been generalized to the polarized as well as nonpolarized liquid liquid interface by Kakiuchi [28] and further by Markin and Volkov [29]. We summarize the essential idea of the electrocapillary equation, so far as it will be required in the following. The electrocapillary equation for a polarized liquid-liquid interface has the form... 

One important advantage of the polarized interface is that one can determine the relative surface excess of an ionic species whose counterions are reversible to a reference electrode. The adsorption properties of an ionic component, e.g., ionic surfactant, can thus be studied independently, i.e., without being disturbed by the presence of counterionic species, unlike the case of ionic surfactant adsorption at nonpolar oil-water and air-water interfaces [25]. The merits of the polarized interface are not available at nonpolarized liquid-liquid interfaces, because of the dependency of the phase-boundary potential on the solution composition. 

At room temperature, unsaturated vapours of the above specified polar and nonpolar liquids do not influence considerably the rate of adsorption and chemical activity of not only adsorbed oxygen layers, but also of acceptors of semiconductor electrons of another type, namely, of alkyl radicals [54]. This is seen from the electric conductivity of ZnO films with adsorbed alkyl radicals or oxygen being invariable in the atmosphere of the saturated vapours of the above specified solvents. In the case of oxygen, this can be also seen from the fact that the oxygen concentration features no decrease. 

The results obtained in above experiments confirm the removal of chemisorbed particles in the process of immersion of the film with preliminary chemisorbed radicals in a liquid acetone. Note that at low pressures of acetone, the CHa-radicals absorbed on ZnO film could be removed only by heating the film to the temperature of 200 - 250°C. Moreover, if the film with adsorbed radicals is immersed in a nonpolar liquid (hexane, benzene, dioxane), or vapours of such a liquid are condensed on the surface of the film, then the effect of removal of chemisorbed radicals does not take place, as is seen from the absence of variation of electric conductivity of the ZnO film after it is immersed in liquid and methyl radicals are adsorbed anew onto its surface. We explain the null effect in this case by suggesting that the radicals adsorbed on the surface of the ZnO film in the first experiment remained intact after immersion in a nonpolar liquid and blocked all surface activity of the adsorbent (zinc oxide). 

In colloid science, colloidal systems are commonly classified as being lyophilic or lyophobic, based on the interaction between the dispersed phase and the dispersion medium. In lyophilic dispersions, there is a considerable affinity between the two constituent phases (e.g., hydrophilic polymers in water, polystyrene in benzene). The more restrictive terms hydrophilic and oleophilic can be used when the external phase is water and a nonpolar liquid, respectively. In contrast, in lyophobic systems there is little attraction between the two phases (e.g., aqueous dispersions of sulfur). If the dispersion medium is water, the term hydrophobic can be used. Resulting from the high affinity between the dispersed phase and the dispersion medium, lyophilic systems often form spontaneously and are considered as being thermodynamically stable. On the other hand, lyophobic systems generally do not form spontaneously and are intrinsically unstable. 

Lado F (1997) Molecular theory of a charged particle in a polarizable nonpolar liquid. J Chem Phys 106(11) 4707—4713... 

Solvated electrons are known to be formed in amines, amides, dimethyl sulfoxide, and many other liquids that will not be discussed here. Note that, except for the yield and time scale of observation, the production of es itself is not related to polarity. Thus, the es absorption spectrum has indeed been observed in nonpolar liquids both at low temperatures and room temperature (Taub and... 

TABLE 9.1 Free-lon Yield in Selected Nonpolar Liquids in the Limit of Zero External Field... 

FIGURE 9.2 Variation of the ion escape probability in a nonpolar liquid with incident electron energy according to the simulations of Bartczak and Hummel. The curve shown is for exponential intra-ionic separation with a b value of 5.12 nm. (See the original reference for other parametric values.) Agreement with various limited experiments in n-hexane is only approximate. Reproduced from Bartczak and Hummel (1997), with the permission of Am. Chem. Soc . 

Table 10.2 lists the critical field Ec in various nonpolar liquids along with the approximate nature of field dependence of mobility when E > Eq. It is remarkable that the higher the zero-field mobility is, the smaller is the value of Ec, indicating the role of field-induced heating. Also note that in the sublinear case, Ec is larger in the case of molecular liquids than for liquefied rare gases,... 

TABLE 10.2 Critical Field E and Nature of Field Dependence of Mobility in Various Nonpolar Liquids... 

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