Determination of partition coefficients of halobenzenes in heptane/water and 1-octanol/water systems and comparison with the scaled particle calculation

Watarai, Hitoshi; Tanak, Makoto.; Suzuki, N.

doi:10.1021/ac00241a023

Cited by 57 publications

(19 citation statements)

References 25 publications

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“…A change of 2% in solvent radius results in a change of ϳ15% in G solv ev (Wilhelm and Battino, 1972). Preliminary results (Lucas, 1976) and evidence from heat capacities of transfer (Desrosiers and Desnoyers, 1976) and partition coefficients (Watarai et al, 1982) suggest that the transfer free energy, ⌬G tr ev , is also sensitive to solvent size. Unfortunately, determining the radii of real molecules, which are not spherical, is somewhat ambiguous.…”

Section: Introductionmentioning

confidence: 90%

Excluded Volume in Solvation: Sensitivity of Scaled-Particle Theory to Solvent Size and Density

Tang

Bloomfield

2000

Biophysical Journal

114

101

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Changes in solvent environment greatly affect macromolecular structure and stability. To investigate the role of excluded volume in solvation, scaled-particle theory is often used to calculate delta G(tr)(ev), the excluded-volume portion of the solute transfer free energy, delta G(tr). The inputs to SPT are the solvent radii and molarities. Real molecules are not spheres. Hence, molecular radii are not uniquely defined and vary for any given species. Since delta G(tr)(ev) is extremely sensitive to solvent radii, uncertainty in these radii causes a large uncertainty in delta G(tr)(ev)-several kcal/mol for amino acid solutes transferring from water to aqueous mixtures. This uncertainty is larger than the experimental delta G(tr) values. Also, delta G(tr)(ev) can be either positive or negative. Adding neutral crowding molecules may not necessarily reduce solubility. Lastly, delta G(tr)(ev) is very sensitive to solvent density, rho. A few percent error in rho may even cause qualitative deviations in delta G(tr)(ev). For example, if rho is calculated by assuming the hard-sphere pressure to be constant, then delta G(tr)(ev) values and uncertainties are now only tenths of a kcal/mol and are positive. Because delta G(tr)(ev) values calculated by scaled-particle theory are strongly sensitive to solvent radii and densities, determining the excluded-volume contribution to transfer free energies using SPT may be problematic.

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Section: Introductionmentioning

confidence: 90%

Excluded Volume in Solvation: Sensitivity of Scaled-Particle Theory to Solvent Size and Density

Tang

Bloomfield

2000

Biophysical Journal

114

101

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“…14 noted the prominent role of the solvent cavity formation process. They concluded that the magnitude of an individual partition coefficient was largely governed by differences in solvent cavity formation energy, which is a function of solute size, as well as the particular solvents involved.…”

Section: Resultsmentioning

confidence: 99%

“…This technique has been shown to provide reliable and consistent results 12 . In addition, Hansch and Leo 13 and Watarai et al 14 have determined heptane/water partition coefficients for alkybenzenes and chlorobenzenes respectively. These studies provide suitable data by which the utility of Equation (7) can be evaluated.…”

Section: A (5)mentioning

confidence: 99%

A theoretical basis for Collander Equations

Hawker

1994

Toxicological & Environmental Chemistry

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Biphasic partition coefficients are important parameters in describing environmental behaviour of chemicals. Collander Equations are linear expressions linking the logarithms of solvent/water partition coefficients (K sw ). Despite their importance, the theoretical basis for these equations is not well developed, limiting their predictive capability. Using Regular Solution Theory, a general equation is developed relating log K sw to the logarithm of the octan-1-ol/water partition coefficient (K ow ). As an example of the applicability of the expression, calculated hexadecane/water (K hw ) and heptane/water (K hepw ) partition coefficients are in satisfactory agreement with available experimentally determined values for homologous solute series of alkanes, alkenes and alkylbenzenes. Agreement is less satisfactory for alkan-1-ols and chlorobenzenes. The theoretical treatment predicts that Collander Equations relating log K sw to log K ow are overall curvilinear, but linear over limited log K ow ranges.

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“…The bioconcentration factors calculated using the residue values from Table 1 and the mean water concentrations up until the date of sampling are shown in Table 2. Literature [6,20] and calculated [21,22] octanolwater partition coefficeints and parachors are also listed in the table. A statistical approach, analysis of variance, was used to establish when the BCFs had reached a constant value.…”

Section: Resultsmentioning

confidence: 99%

Rainbow Trout Bioconcentration of Some Halogenated Aromatics From Water at Environmental Concentrations

Oliver¹,

Niimi²

1984

Environ Toxicol Chem

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The bioconcentration of 10 brominated and chlorinated aromatics by rainbow trout at ng/L concentrations, approaching environmental levels, has been studied. Seven of the compounds (3,4-dichlorobenzotrifluoride; 2,4,5-trichlorotoluene; 2,3,4-trichloroanisole; 1,4-dichloronapthalene; 1,3-dibromobenzene; 1,3,5-tribromobenzene; 1,2,4-tribromobenzene) reached a steady equilibrium concentration in the fish over the 90 day study period. Fish residue levels for the other three compounds (2,4-dichlorodiphenyl-ether; 1,2,4,5-tetrabromobenzene; 4 4'-dichlorobiphenyl) continued to increase over the entire study period. A good linear correlation (r = 0.79) between log bioconcentration factor (BCF) and log octanol-water partition coefficient (K) was found for the seven equilibrated compounds with a slope of 0.99. A good correlation between log BCF and parachor was also found for selected chemicals from this and an earlier study. Compounds that did not equilibrate plotted well below the log BCF versus log K line and had K values of > lo5 and parachors (surface tension corrected molar volumes) > 400. 2'

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Determination of partition coefficients of halobenzenes in heptane/water and 1-octanol/water systems and comparison with the scaled particle calculation

Cited by 57 publications

References 25 publications

Excluded Volume in Solvation: Sensitivity of Scaled-Particle Theory to Solvent Size and Density

Excluded Volume in Solvation: Sensitivity of Scaled-Particle Theory to Solvent Size and Density

A theoretical basis for Collander Equations

Rainbow Trout Bioconcentration of Some Halogenated Aromatics From Water at Environmental Concentrations

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