Vapour pressures, aqueous solubility, Henry's law constants and air/water partition coefficients of 1,8-dichlorooctane and 1,8-dibromooctane

New data on the vapour pressures and aqueous solubility of 1,8-dichlorooctane and 1,8-dibromooctane are reported as a function of temperature between 20 °C and 80 °C and 1 °C and 40 °C, respectively. For the vapour pressures, a static method was used during the measurements which have an estimated uncertainty between 3% and 5%. The aqueous solubilities were determined using a dynamic saturation column method and the values are accurate to within ±10%. 1,8-Dichlorooctane is more volatile than 1,8-dibromooctane in the temperature range covered (p_sat varies from 3 to 250 Pa and from 0.53 to 62 Pa, respectively) and is also approximately three times more soluble in water (mole fraction solubilities at 25 °C of 5.95 × 10⁻⁷ and 1.92 × 10⁻⁷, respectively). A combination of the two sets of data allowed the calculation of the Henry’s law constants and the air water partition coefficients. A simple group contribution concept was used to rationalize the data obtained.     

Aqueous solubility, Henry's law constants and air/water partition coefficients of n-octane and two halogenated octanes

New data on the aqueous solubility of n-octane, 1-chlorooctane and 1-bromooctane are reported between 1 degree C and 45 degrees C. Henry's law constants, K(H), and air/water partition coefficients, K(AW), were calculated by associating the measured solubility values to vapor pressures taken from literature. The mole fraction aqueous solubility varies between (1.13-1.60)x10(-7) for n-octane with a minimum at approximately 23 degrees C, (3.99-5.07)x10(-7) for 1-chlorooctane increasing monotonically with temperature and (1.60-3.44)x10(-7) for 1-bromooctane with a minimum near 18 degrees C. The calculated air-water partition coefficients increase with temperature and are two orders of magnitude lower for the halogenated derivatives compared to octane. The precision of the results, taken as the average absolute deviations of the aqueous solubility, the Henry's law constants, or the air/water partition coefficients, from appropriate smoothing equations as a function of temperature is of 3% for n-octane and of 2% and 4% for 1-chlorooctane and 1-bromooctane, respectively. A new apparatus based on the dynamic saturation column method was used for the solubility measurements. Test measurements with n-octane indicated the capability of measuring solubilities between 10(-6) and 10(-10) in mole fraction, with an estimated accuracy better than +/-10%. A thorough thermodynamic analysis of converting measured data to air/water partition coefficients is presented.     

Evaluation of the dependence of aqueous solubility of nitro compounds on temperature and salinity: a COSMO-RS simulation

The solubility in pure and saline water at various temperatures was calculated for selected nitro compounds (nitrobenzene, 1,3,5-trinitrobenzene, 2-nitrotoluene, 3-nitrotoluene, 4-nitrotoluene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, 2,3-dinitrotoluene, 3,4-dinitrotoluene, 2,4,6-trinitrotoluene) using the Conductor-like Screening model for Real Solvents (COSMO-RS). The results obtained were compared with experimental values. The COSMO-RS predictions have shown high accuracy in reproducing the trends of aqueous solubilities for both temperature and salinity. The proposed methodology was then applied to predict the aqueous solubilities of 19 nitro compounds in the temperature range of 5-50 °C in saline solutions. The salting-out parameters of the Setschenow equation were also calculated. The predicted salting-out parameters were overestimated when compared to the measured values, but these parameters can still be used for qualitative estimation of the trends.     

Estimation of aqueous solubility of organic compounds by using the general solubility equation

The general solubility equation (GSE) proposed by Jain and Yalkowsky was used to estimate aqueous solubility of 1026 non-electrolytes. The only parameters used in the GSE are melting points (MP) and octanol-water partition coefficients (Kow). No fitted parameters and no training set are employed in the GSE. The experimental solubility values were taken from the AQUASOL dATAbASE. The average absolute error and the root-mean-square error in the solubility estimates are 0.38 and 0.53 log units, respectively. Thus, with an observed MP and calculated Kow; the users can obtain a reasonable estimation of the aqueous solubility of any organic non-electrolyte.     

The aqueous solubility of twenty-seven insecticides and related compounds

The aqueous solubilities of 27 insecticides and related compounds were determined. Diazinon, fensulfothion and paraoxon had solubilities greater than reported in the literature. The presence of impurities and/or additional components in the mixture altered the measured solubility values. Addition of acetone in amounts up to 1% (volume) produced increases in parathion solubility up to 11%. The pH values of the equilibrated solubility systems were, in most instances, acidic and, in several instances, were in the pH 3-4 range.     

Fat solubility — A property of environmental relevance?

Solubilities in fats ranging from 0.88 g l^?1 to completely miscible are reported for twelve organic chemicals. Comparison of these and other literature values with bioconcentration factors and octanol: water partition coefficients indicate that fat solubility is not a reliable predictor for either parameter. The results for the solubilities of seven chemicals in eight different fats cover a restricted range, indicating that the composition of the fat is not a critical parameter in determining the solubility.     

Application of quantum-chemical approximations to environmental problems: Prediction of physical and chemical properties of TNT and related species

This paper presents accurate predictions of ecologically important properties of nitroaromatic compounds and their derivatives, including vapor pressure, Henry's law constants, water solubility, octanol/water partition coefficients, heats of formation and ionization potentials. The proposed technique of calculations was based on quantum-chemical methods. The relationship between the chemical structure and mentioned physico-chemical parameters of such widespread military produced contaminants as trinitrotoluene and its derivatives was considered. We revealed that the DFT level of theory combined with the COSMO-RS technique is able to predict the studied parameters with an accuracy that results in error bars of less then one logarithmic unit.     

Further water solubility determinations of insecticidal compounds

Abstract

The aqueous solubility of 39 insecticidal and related compounds was determined at 20±1.5°C, using a previously described shaking and centrifugation method. Fenamiphos, fenthion and methi‐dathion produced values substantially less than those reported in the literature whereas, aminocarb, diazinon, dicapthon, pirimiphos‐ethyl and pirimiphos‐methyl gave solubilities substantially greater than reported literature values.     

The aqueous solubility of twenty‐seven insecticides and related compounds.

Abstract

The aqueous solubilities of 27 insecticides and related compounds were determined. Diazinon, fensulfothion and paraoxon had solubilities greater than reported in the literature. The presence of impurities and/or additional components in the mixture altered the measured solubility values. Addition of acetone in amounts up to 1% (volume) produced increases in parathion solubility up to 11%. The pH values of the equilibrated solubility systems were, in most instances, acidic and, in several instances, were in the pH 3–4 range.     

Radiosynthesis of perfluorooctanesulfonate (PFOS) and perfluorobutanesulfonate (PFBS), including solubility, partition and adhesion studies

Here, we describe for the first time the synthesis of [³⁵S] PFOS and [³⁵S] PFBS with sulfur-35 enriched sulfur dioxide as the radiolabelled reagent, resulting in 2.5 and 2.3 mCi of product, respectively. Basic information concerning the physicochemical properties of perfluorooctanesulfonate (PFOS), perfluorobutanesulfonate (PFBS) and perfluorooctanoic acid (PFOA) are still limited. Hence, we utilized these radiolabelled perfluoroalkanesulfonates (PFSAs), as well as carbon-14 labelled perfluorooctanoic acid ([¹⁴C] PFOA) to determine some basic characteristics of physiological and experimental significance.The solubility of PFOS in buffered aqueous solutions at pH 7.4 was found to be severely reduced in the presence of potassium and sodium ions, which, however, did not reduce the solubility of PFOA or PFBS. PFOS was found to adhere to a small extent to polypropylene and polystyrene, whereas no such adhesion of PFOA or PFBS was detected. The extents of adhesion of PFOS and PFOA to glass were found to be 20% and 10%, respectively. For the first time, the partition coefficients for PFOS, PFBS and PFOA between n-octanol and water were determined experimentally, to be −0.7, −0.3, and 1.4, respectively, reflecting the difference in the amphiphilic natures of these molecules.     

Estimating the aqueous solubility of aromatic hydrocarbons by high performance liquid chromatography

Empirical equations which correlate high performance liquid chromatography capacity factor (k′) to aromatic hydrocarbon aqueous solubility are developed. The correlations of k′ to octanol-water partition coefficients, and k′ to hydrocarbon surface area are also shown.     

Biosurfactant-enhanced solubilization of NAPL mixtures

Remediation of nonaqueous phase liquids (NAPLs) by conventional pump-and-treat methods (i.e., water flushing) is generally considered to be ineffective due to low water solubilities of NAPLs and to mass-transfer constraints. Chemical flushing techniques, such as surfactant flushing, can greatly improve NAPL remediation primarily by increasing the apparent solubility of NAPL contaminants. NAPLs at hazardous waste sites are often complex mixtures. However, the equilibrium and nonequilibrium mass-transfer characteristics between NAPL mixtures and aqueous surfactant solutions are not well understood. This research investigates the equilibrium solubilization behavior of two- and three-component NAPL mixtures (containing akylbenzenes) in biosurfactant solutions. NAPL solubilization is found to be ideal in water (i.e., obeys Raoult's Law), while solubilization in biosurfactant solutions was observed to be nonideal. Specifically, the relatively hydrophobic compounds in the mixture experienced solubility enhancements that were greater than those predicted by ideal enhanced solubilization theory, while the solubility enhancements for the relatively hydrophilic compounds were less than predicted. The degree of nonideality is shown to be a nonlinear function of the NAPL-phase mole fraction. Empirical relationships based on the NAPL-phase mole fraction and/or micelle-aqueous partition coefficients measured in single-component NAPL systems are developed to estimate values for the multicomponent partition coefficients. Empirical relationships that incorporate both the NAPL-phase mole fraction and single-component partition coefficients yield much improved estimates for the multicomponent partition coefficient.     

Estimation of the aqueous solubility of complex organic compounds

The aqueous solubility of organic compounds depends on two contributing parameters: the ideal solubility and the activity coefficient. The methods available for the prediction of aqueous solubility have the ideal solubility term in common. They differ in the way they account for the activity coefficient. Various empirical and theoretical methods for predicting activity coefficients are compared in this report. The methods were first used with a Training Set of solutes. The same methods were then applied to a Test Set of solutes, which consisted of a series of compounds of pharmaceutical and environmental relevance. The Test Set encompassed a wide variety of chemical structures and high degree of structural complexity. Only those methods with a sound theoretical rationale are useful for both the Training and Test sets. A comparative evaluation of the methods tested was made through the quantification of the accuracy of their predictions and their range of applicability.     

Aqueous solubility and n-octanol/water partition coefficient correlations

Studies of the fate of chemicals require the knowledge of numerous parameters, among which of utmost importance are the water solubility and the n-octanol/water partition coefficient.

Numerous writers have demonstrated that there is a close correlation between these two parameters. The literature offers about fifteen cases of correlations between solubility and n-octanol/water partition coefficient with, for some of them, and for solids, a third variable: the fusion point. Unfortunately, the coefficients are often the results of theoretical considerations and the size of the data base is often small.

A study carried out on 300 products shows clearly the importance of the size of the data base. It is demonstrated that the coefficients obtained in practice are different from those which had been calculated theoretically. In particular, the introduction of a fusion point correction appears to be justified only to a limited extent.

This analysis has shown that there is a need to reexamine the theoretical approach and determine why the coefficients of the regression equation do not appear to adopt the values excepted from theoretical considerations.     

Study of fuel oxygenates solubility in aqueous media as a function of temperature and tert-butyl alcohol concentration

Methyl tert-butyl ether (MTBE) is the most widely used oxygenate in gasoline blending and has become one of the world’s most widespread groundwater and surface water pollutants. Alternative oxygenates to MTBE, namely ethyl tert-butyl ether (ETBE), tert-amyl ether (TAME) and diisopropyl ether (DIPE) have been hardly studied yet. The solubility of these chemicals is a key thermodynamic information for the assessment of the fate and transport of these pollutants. This work reports experimental data of water solubility at the range from 278.15 to 313.15 K and atmospheric pressure of ethers used in fuels (MTBE, ETBE, TAME and DIPE) due to the strong influence of temperature on its trend. From the experimental data, temperature dependent polynomials were fitted, thermodynamic parameters were calculated and theoretical models were used for prediction. Finally, the tert-butyl alcohol (TBA) influence in the solubility of MTBE and ETBE in aqueous media was studied.     

Vapour pressures, aqueous solubilities, Henry's law constants, partition coefficients between gas/water (Kgw), n-octanol/water (Kow) and gas/n-octanol (Kgo) of 106 polychlorinated diphenyl ethers (PCDE)

Modelling the environmental fate of persistent organic pollutants like polychlorinated diphenyl ethers (PCDE) requires the knowledge of a number of fundamental physico-chemical properties of these compounds. We report here the physico-chemical properties of 106 PCDEs, which are over 50% of all possible congeners. Vapour pressures P(OL), water solubilities S(H2O), and n-octanol/water partition coefficients K(OW) were determined with chromatographic methods. With these experimental data the Henry's law constants H, gas/water K(GW) and gas/n-octanol K(GO) partition coefficients were calculated. Vapour pressures and water solubilities and n-octanol/water partition coefficients of the PCDEs are close to those of similar groups of organochlorine compounds like polychlorinated biphenyls (PCBs) and dibenzofurans (PCDFs). A similar environmental fate can be predicted and was partially already been observed.     

Physicochemical properties of selected polybrominated diphenyl ethers and extension of the UNIFAC model to brominated aromatic compounds

The aqueous solubilities (S(w)) at various temperatures from 283 K to 308 K and 1-octanol/water partition coefficients (K(ow)) for four polybrominated diphenyl ethers (PBDEs: 4,4'-dibromodiphenyl ether (BDE-15), 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5-pentabromodiphenyl ether (BDE-99), and 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153)) were measured by the generator column method. The S(w) and K(ow) data revealed the effect of bromine substitution and basic structure on S(w) and K(ow). To estimate the infinite dilution activity coefficients (gamma(i)(w,infinity)) of the PBDEs in water from the S(w) data, enthalpies of fusion and melting points for those compounds were measured with a differential scanning calorimeter. Henry's Law constants (H(w)) of the PBDEs were derived from the determined gamma(i)(w,infinity) and literature vapor pressure data. Some physicochemical characteristics of PBDEs were also suggested by comparing the present property data with that of polychlorinated dibenzo-p-dioxins, brominated phenols and brominated benzenes in past studies. Furthermore, in order to represent different phase equilibria including solubility and partition equilibrium for other brominated aromatic compounds using the UNIFAC model, a pair of UNIFAC group interaction parameters between the bromine and water group were determined from the S(w) and K(ow) data of PBDEs and brominated benzenes. The ability of the determined parameters to represent both properties of brominated aromatics was evaluated.     

Correlating the physical-chemical properties of phthalate esters using the 'three solubility' approach

A quantitative structure-property relationship (QSPR) method for the correlation of physical-chemical properties and partition coefficients, namely the 'three solubility' approach, is described and applied to a group of 22 phthalate esters. The solubilities or 'apparent-solubilities' of these substances in the liquid state are compiled and correlated against Le Bas molar volume in the three primary media of air, water and octanol. From these solubilities the air-water (K(AW)), octanol-water (K(OW)) and octanol-air (K(OA)) partition coefficients are deduced. Estimated solubilities in water and octanol-water partition coefficients are shown to compare favourably with more recent accurate measurements. A set of selected values is presented, with error limits, which is recommended for use in modelling and assessment studies. Some environmental implications are discussed of the large range in property values for this series.     

Parameters for predicting fate of organochlorine pesticides in the environment (I) Octanol-water and air-water partition coefficients

Octanol-water partition coefficients and air-water partition coefficients of 10 principal organochlorine pesticides were obtained as basic data for predicting their fate in environment. The octanol-water partition coefficients were in the wide range from 10 to 10⁶ and approximately correlated with the solubilities in water. The air-water partition coefficients were also in the wide range from 10⁻⁷ to 10⁻², and the values for chloropicrin, dichlorvos, DCIP and quintozene were relatively high.