Benzene partition coefficient

Let us consider a specific example, viz., the extraction of a solution of 4 Og. of n-butyric acid in 100 ml. of water at 15° with 100 ml. of benzene at 15°. The partition coefficient of the acid between benzene and water may be taken as 3 (or J between water and benzene) at 15°. For a single extraction with benzene, we have ... 

For ammonium surfactants there is evidence for the existence of an additional specific interaction between the headgroups of the surfactant and the aromatic solubilisate . This is in line with the observation that partition coefficients for benzene in CTAB solutions are much higher than those for... 

Calculations usirig this value afford a partition coefficient for 5.2 of 96 and a micellar second-order rate constant of 0.21 M" s" . This partition coefficient is higher than the corresponding values for SDS micelles and CTAB micelles given in Table 5.2. This trend is in agreement with literature data, that indicate that Cu(DS)2 micelles are able to solubilize 1.5 times as much benzene as SDS micelles . Most likely this enhanced solubilisation is a result of the higher counterion binding of Cu(DS)2... 

Extraction from Aqueous Solutions Critical Fluid Technologies, Inc. has developed a continuous countercurrent extraction process based on a 0.5-oy 10-m column to extract residual organic solvents such as trichloroethylene, methylene chloride, benzene, and chloroform from industrial wastewater streams. Typical solvents include supercritical CO9 and near-critical propane. The economics of these processes are largely driven by the hydrophihcity of the product, which has a large influence on the distribution coefficient. For example, at 16°C, the partition coefficient between liquid CO9 and water is 0.4 for methanol, 1.8 for /i-butanol, and 31 for /i-heptanol. 

Other important determinants of the effects of compounds, especially solvents, are their partition coefficients, e.g., blood-tissue partition coefficients, which determine the distribution of the compound in the body. The air-blood partition coefficient is also important for the absorption of a compound because it determines how quickly the compound can be absorbed from the airspace of the lungs into the circulation. An example of a compound that has a high air-blood partition coefficient is trichloroethane (low blood solubility) whereas most organic solvents (e.g., benzene analogues) have low air-blood partition coefficients (high blood solubility). 

If the substance shared between two solvents can exist in different molecular states in them, the simple distribution law is no longer valid. The experiments of Berthelot and Jungfleiscli, and the thermodynamic deduction show, however, that the distribution law holds for each molecular state separately. Thus, if benzoic acid is shared between water and benzene, the partition coefficient is not constant for all concentrations, but diminishes with increasing concentration in the aqueous layer. This is a consequence of the existence of the acid in benzene chiefly as double molecules (C6H5COOH)2, and if the amount of unpolymerised acid is calculated by the law of mass action (see Chapter XIII.) it is found to be in a constant ratio to that in the aqueous layer, independently of the concentration (cf. Nernst, Theoretical Chemistry, 2nd Eng. trans., 486 Die Verteilnngssatz, W. Hertz, Ahrens h annulling, Stuttgart, 1909). 

Aqueous solutions are not suitable solvents for esterifications and transesterifications, and these reactions are carried out in organic solvents of low polarity [9-12]. However, enzymes are surrounded by a hydration shell or bound water that is required for the retention of structure and catalytic activity [13]. Polar hydrophilic solvents such as DMF, DMSO, acetone, and alcohols (log P<0, where P is the partition coefficient between octanol and water) are incompatible and lead to rapid denaturation. Common solvents for esterifications and transesterifications include alkanes (hexane/log P=3.5), aromatics (toluene/2.5, benzene/2), haloalkanes (CHCI3/2, CH2CI2/I.4), and ethers (diisopropyl ether/1.9, terf-butylmethyl ether/ 0.94, diethyl ether/0.85). Exceptionally stable enzymes such as Candida antarctica lipase B (CAL-B) have been used in more polar solvents (tetrahydrofuran/0.49, acetonitrile/—0.33). Room-temperature ionic liquids [14—17] and supercritical fluids [18] are also good media for a wide range of biotransformations. 

Organic solvent(s) Partition coefficients Miscible with common solvents and thinners, vegetable oilsb No data Soluble in most organic solvents except glycerol Soluble in benzene, CHCI3, ether, acetone8... 

Organic solvent(s) Partition coefficients Soluble in ether, benzene carbon disulfide, alcoholb No data Soluble in alcohol, benzene, ether15 soluble in acetic acidg... 

For substituents on benzene, lipophilicities are given by values of kx, as measured by the following equation (Scheme 1.1), where P values are the octanol/water partition coefficients. 

Fig. 5. Relationship between the distribution (partition) coefficient on dimethyl dihydrogenated tallow montmorillonite for a range of non-ionic organic pollutants and their corresponding solubility in water. BHC is benzene hexachloride, the y-isomer of which is known as lindane aroclor 1232 and aroclor 1252 denote mixtures of polychlorinated biphenyls containing about 32 and 52% chlorine, respectively. After Beall (2003).

The Level I calculation suggests that if 100,000 kg (100 tonnes) of benzene are introduced into the 100,000 km2 environment, 99% will partition into air at a concentration of 9.9 x 10-7 g/m3 or about 1 pg/rn3. The water will contain nearly 1% at a low concentration of 4 pg/rn3 or equivalently 4 ng/L. Soils would contain 5 x 10-6 pg/g and sediments about 9.7 x 10 6 pg/g. These values would normally be undetectable as a result of the very low tendency of benzene to sorb to organic matter in these media. The fugacity is calculated to be 3.14 x 10-5 Pa. The dimensionless soil-water and sediment-water partition coefficients or ratios of Z values are 2.6 and 5.3 as a result of a Koc of about 55 and a few percent organic carbon in these media. There is little evidence of bioconcentration with a very low fish concentration of 3.0 x FT5 pg/g. The pie chart in Figure 1.7.6 clearly shows that air is the primary medium of accumulation. 

Miller, M. M., Ghodbane, S., Wasik, S. R, Tewari, Y. B., Martire, D. E. (1984) Aqueous solubilities, octanol/water partition coefficients and entropies of melting of chlorinated benzenes and biphenyls. J. Chem. Eng. Data 29, 184-190. 

Reported octanol-water partition coefficients and octanol-air partition coefficients of benzene at various temperatures ... 

Measurements of aqueous solubility and partition coefficient between cellulose acetate and water were compared for thirty disperse dyes and an approximate inverse relationship was postulated [60]. This can only be valid to a limited extent, however, because the partition ratio also depends on the saturation solubility of the dye in cellulose acetate. This property varies from dye to dye and is not directly related to aqueous solubility. The solubilities of four dyes in a range of solvents were compared with their saturation values on cellulose acetate. Solubilities in benzene showed no significant correlation. With the other solvents the degree of correlation increased in the order ethanol < ethyl acetate < 20% aqueous diethylene glycol diacetate (CH3COOCH2CH2OCH2CH2OCOCH3). The last-named compound was suggested as a model with polar groups similar to those in cellulose acetate [86]. 

Paracyclophane also has a compact structure in solution, as is readily seen on comparing its partition coefficient with that of p-xylene for the system octanol/water 32>. Rigid superposition of the benzene rings leads to an intramolecular delocalization of the hydrophobic -electron clouds and hence to an increased affinity for the aqueous phase. Accordingly, the logarithm of the partition coefficient is found to be smaller than the value observed for p-xylene, and not twice as large, as would be expected for completely hydrophobic surfaces. 

Figure 3.3 SPMD-water partition coefficients (ml mL units) as a function of log Kqw for PAHs—filled circles Huckins et al. (1999), filled triangles Huckins et al. (2004) phenanthrene, PCB 52, and p,p -DDE—open triangles Huckins et al. (2002a) chlorobenzenes, PAHs, and PCBs—squares Booij et al. (2003a) pesticides—filled diamonds Sabaliunas and Sodergren (1997) and HCHs—open diamonds Vrana and Schiiurmann (2002). Additional kjw data were calculated for PCBs (asterisks) and alkylated benzenes (crosses) using the fCmw data from Lefkovitz et al. (1996) and Reynolds et al. (1990), and the data from Chiou (1985).

Niimi, A.J., Lee, H.B., and Kissoon, G.P. Octanol/water partition coefficients and bioconcentration factors of chloronitro-benzenes in rainbow trout Salmogairdneri), Environ. Toxicol. Chem., 8(9) 817-823, 1989. 

Organic solvents Partition coefficients Very soluble in alcohol slightly soluble in benzene Dean 1985... 

Solubility water at 20 °C organic solvent(s) Partition coefficients Almost insoluble 3.1 mg/L 4 mg/L (22 °C) Soluble in alcohol, benzene. Glacial acetic acid Merck 1989 DCMA 1989 Banerjee et al. 1978 Merck 1989... 

It is expected that the hydrophilic groups would make the compound less oleophilic, and thus decrease the octanol-water partition coefficient, or log P, which is also demonstrated in figure 6.4. When multiple functional groups are added, there are often interactions among them, so that the results are not simply additive. Figure 6.5 shows that each addition of chlorine to benzene from one to three would depress the water solubility of these benzene derivatives by a factor of six to eight, but the totally chlorinated hexachlorobenzene has a water solubility that is six orders of magnitude smaller than benzene. The partition coefficients show a very consistent pattern in parallel with... 

Figure 6.4 The water solubility and log partition coefficients of benzene derivatives...

A large, sealed fish tank - consisting of 20 m of water, 10 m of air, 1 m of sediment, and 0.2 m of fish and other biological organisms - has 100 g of benzene accidentally spilled into it. What will be the eventual (equilibrium) concentrations and mass in each phase The fraction of organic carbon in the sediments has been determined to be 0.01. The density of the sediments has been determined to be 2g/cm. The octanol-water partitioning coefficient for benzene is 138. 

In the preceding example, methane gave a sharp spike in 42 s, whereas benzene required 251 s. The open tubular chromatography column has an inner diameter of 250 pm and is coated on the inside with a layer of stationary phase 1.0 pm thick. Estimate the partition coefficient (K = Cs/Cm) for benzene between stationary and mobile phases and state what fraction of the time benzene spends in the mobile phase. 

Butanoic acid has a partition coefficient of 3.0 (favoring benzene) when distributed between water and benzene. Find the formal concentration of butanoic acid in each phase when 100 mL of 0.10 M aqueous butanoic acid is extracted with 25 mL of benzene (a) at pH 4.00 and (b) at pH 10.00. 

In the example shown in Figure 1.1.1, the water solubilities and the octanol-water partition coefficients of benzene, chlorobenzene, and toluene are related directly through the QPPR Kov/ =f(Sw). In this case, only one property, the water solubility, is used as the predictor variable. Chlorobenzene, the query, is considered similar to toluene and benzene because it contains one aromatic ring. The chlorine substituent is hydrophobic and bulky, similar to the methyl group of toluene. If the range of compounds is expanded to n other compounds, the applicability of the QPPR is expanded to all compounds similar to the set of n compounds included in the training set. 

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