Partition/solubility value

The binding constants of a number of compounds were measured using dialysis, solubility and sorption techniques. The solubility technique was used for compounds which were not radiolabeled. All data was collected at pH = 8.3. The binding constants were then compared to the octanol/water partition coefficients for the compounds and the molar solubilities of the compounds. The data is presented in Table II. The Kow values were taken from the literature.18 22-2 The solubility values were determined in this research with the exception of DDT and Lindane, which were taken from the literature. A plot of log Kc vs. log Kow is presented in Figure 5. The slope of this line is 0.71, the intercept is 0.75 and the value of the correlation coefficient is 0.9258. The regression is highly significant... 

The solubilities in water and octanol of the pyrazino[l,2-A]quinazolones 23 (R1 =Me, R4 = H R1 = R4 = Me) with various N-2 substituents were determined. Solubility ratios and partition coefficient values were fitted to a predictive equation to evaluate the possibility of aqueous solubility estimates <1997IJP233>. 

Experimental values of the fullerene C60 solubility, values of the DCW for organic solvents under consideration, and the details of partition of the data into the training and test sets are shown in Table 14.4. The considered model is displayed in Figs. 14.1 and 14.2, for training and test sets, respectively. The model of the fullerene C60 solubility obtained in the first ran of the Monte Carlo method optimization is as follows ... 

There are two methods for crossing the BBB passive diffusion or active transport. Passive diffusion is the route preferred by most neuroactive drugs. Lipid solubility is a desired chemical property for a molecule to diffuse across the BBB. For a molecule to cross the BBB by passive diffusion it should have a molecular weight less than 650 g/mol and should have a logP (logarithm of the octanol-water partition coefficient) value... 

The mobility and bioavailability of CPs, and thus their bioremediation, are affected by their chemical and physical properties. The solubility of CPs in water decreases as the number of chlorine substituents increases. In addition, the increase in the number of chlorosubstituents in the phenol ring increases the lipophilicity of CPs and thus their tendency to bioaccumulate. The water solubilities, pKa (acidity constant) and pK0W (octanol-water partition constant) values for environmentally important CPs are summarized in Figure 8.1. 

Solving the equations derived for practical mass transport problems requires values for fundamental material constants which describe the solubility of the diffusant in the polymer matrix or the partition coefficient of the diffusant between two contacting media. This chapter deals with estimation methods for solubility values and partition constants. 

There already exists a substantial literature devoted to the estimation of various material properties with the help of additive structual increments (Reid et. al, 1987, Van Krevelen, 1990). The regular solution theory in combination with additive structural increments has a wide application for estimating the relative solubilities of organic substances in polymers and the solubility of polymers in various solvents (Barton, 1983) and will be described later in this chapter. When estimating partition coefficient values, one is quickly confronted with this method s application limits, particularly with polar and non-polar structures, for example the partitioning of substances between polyolefins and alcohol (Baner and Piringer, 1991). 

In ionic surfactant systems, the partition coefficient between excess phases is often found to be unity, hence an optimum formulation is defined by SAD = 0. With polyethoxylated surfactants, the CMC in water is often extremely low, whereas the monomer solubility in many oils is high. Consequently, the assumption of unit activity coefficient is not valid anymore and the partition coefficient between excess phases is not unity. In such cases, the partition coefficient value at optimum formulation is taken as a reference, and the deviation from this reference, the so-called hydrophilic-lipophilic deviation (HLD) is defined by dividing by RT to make the yardstick dimensionless [34]. 

RDX has a vapor pressure of 1.0 10" mm Hg (Army 1987a). It may exist in both the vapor phase and particulate phase in the atmosphere (Eisenreich et al. 1981). The solubility of RDX in water is low to negligible (Merck 1989 HSDB 1994). However, the following water solubility values have been reported 21.8-21.9 mg/L at 10 °C, 38.4-38.9 mg/L at 20 °C, and 66.7-67 mg/Lat30 °C(Army 1983b). RDX is slightly soluble in methanol, ether ethyl acetate, and glacial acetic acid (Merck 1989). The Henry s law constant for RDX (1.2 10" atm-m 3/mol) (McKone and Layton 1986) indicates that RDX tends to partition equally between the atmosphere and water (Eisenreich et al. 1981) and that volatilization is a slow transport process (Lyman et al. 1982). 

The fate of a chemical, after an organism is exposed to it, is also an important factor in determining its toxic effects. It involves all possible interactions or joint effects of the chemical with other chemicals already existing in the organism. In this context, the water solubility, tissue reactivity and blood-to-gas-phase partition coefficient values of toxicons, are all important with regard to the VOC. 

If a chemical is completely excreted, then succeeding doses have no increased effect, hut if a residue remains, then it is possible for the second dose to add to the first and, if doses are repeated often enough, to reach a level high enough to be toxic. In this context, it is obvious that, the water solubility - tissue reactivity and blood to gas phase partition coefficient values of the toxicants are all important in cases of exposure to gases indoors. 

Inversely, the presence of ethanol and other alcohols in hydroalcoholic preparations may cause loss of solubility of hydrophilic peptides. In these products polypeptides with high hydrophobicity are preferred. The coefficient of ripartition 2-butanol/water (as nitrogen-partition coefficient) is used to estimate the lipophilic/hydrophilic balance of proteins for hydrophobic hydrolysates the nitrogen-partition coefficient value is 0.1-0.15 and lower for more hydrophilic derivatives (129). 

A set of fluorous ponytails, perfluoropolyalkylethers, were incorporated into the Wilkinson-type Rh(I) complex (Scheme 7.22) [34]. The fluorous Rh(I) complexes were preferentially soluble in fluorous solvents and used as recyclable biphase hydrogenation catalysts with less than 0.35% Rh leaching. It was found that the fluorous Rh(I) complexes had lower partition coefficient values than their... 

As can be seen in Figure 5-17, some search fields (e.g., POW [= Power]) do not need any input in the search mask this means that all entries with any content of those Helds are retrieved. However, other fields always demand an input. In case the input is omitted (for example for the decadic logarithm of the partition coefficient), a corresponding error message results. Since the PCB are more soluble in the organic phase, the input of that Field is restricted to positive values. 

The isolation and/or identification of nonpolymerics has been described, including analyses for residual monomers (90,102,103) and additives (90,104—106). The deterrnination of localized concentrations of additives within the phases of ABS has been reported the partitioning of various additives between the elastomeric and thermoplastic phases of ABS has been shown to correlate with solubility parameter values (41). 

Table S.6 Partitioned values of the solubility parameter (after Hansen )...

Closely related to water solubility as a polarity measure is the partition coefficient of a substance between water and an immiscible organic solvent. Most commonly the organic solvent is selected to be n-octanol, and the symbol P is given to the octanol/water partition coefficient. Then log P is a quantitative measure of hydro-phobicity and, therefore, of nonpolarity. Table 8-3 gives log P values for many of... 

The BUSES model provides an estimate of the organic carbon/water partition coefficient (Koc) based on the octanol/water partition coefficient (Kow)- From these data, it is evident that the methyltins are less likely to partition onto organic carbon (in sediments, soils, biota) than are the butyl- and octyltin compormds due to then-lower partition coefficients and higher water solubilities. The 7/oc value can then be used to derive sohds/water partition coefficients in suspended matter, in sediment, and in soil using values of 10%, 5%, and 2% for organie carbon, representing typical organic carbon contents of suspended matter, sediment, and soil, respeetively. 

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