Organic mixture-water partitioning

Tewari, Y.B., Martire, D.E., Wasik, S.P., Miller, M.M. (1982a) Aqueous solubilities and octanol-water partition coefficients of binary liquid mixtures of organic compounds at 25°C. J. Solution Chem. 11, 435 445. 

Hexane (100 mL) is added to the reaction mixture causing more white precipitate to form. The mixture is filtered by suction, and the collected solids are washed with two 50-mL portions of hexane. The combined filtrate and washings are partitioned with 200 mL of a mixture (1 3 v/v) of saturated potassium carbonate solution and water (Note 8). The aqueous phase is extracted with three 200-mL portions of hexane. The combined organic phases are partitioned with 100 mL of saturated sodium chloride, dried thoroughly over anhydrous sodium sulfate and concentrated under reduced pressure to afford 65-75 g of crude product. A small amount of additional crude material can be isolated by continuously extracting the combined aqueous layers with hexane for 3 hr. 

The reaction mixture was partitioned between diethyl ether (60 mL) and water (30 mL). The organic layer was washed with water (2 x 30mL), brine (30mL), and dried over MgS04. After concentration on a rotary evaporator, the oily residue was distilled using a Kugelrohr apparatus (120°/0.07 mbar) to yield 5.35 g (92 %) of (S)-ethyl 3-hydroxy-3-phenylpropanoate with 98 % ee. 

Figure 5.6 Illustration of the effect of a completely water-miscible solvent (CMOS, i.e., methanol) on the activity coefficient of organic compounds in water-organic solvent mixtures decadic logarithm of the activity coefficient as a function of the volume fraction of methanol. Note that the data for naphthalene (Dickhut et al., 1989 Fan and Jafvert, 1997) and for the two PCBs (Li and Andren, 1994) have been derived from solubility measurements whereas for the anilins (Jayasinghe etal., 1992), air-water partition constants determined under dilute conditions have been used to calculate y,f.

To evaluate the effects of salts or organic cosolvents on air-water (or more correctly, air-aqueous phase or air-organic solvent/water mixture) partitioning, we may simply apply the approaches discussed in Section 5.4 (Eqs. 5-27 and 5-29). Thus, knowing how salt affects a compound s aqueous solubility, while having no effect on its saturation vapor pressure, we deduce that the impact of salt on Ki3V/ may be expressed by ... 

To a solution of 2-tosylaminodithiane in acetone was added methyl iodide (typically a 10-fold excess) and the solution was heated under reflux for 1 h. A few drops of water were then added and heating was continued for 4h. The resulting mixture was partitioned between EtOAc and H20. The organic layer was washed with brine, dried and the solvent was removed in vacuo to yield crude 2-tosylaminocarbonyl compounds. Chromatographic purification of these compounds gave analytically pure... 

Common unspecific mode of action of all organic compounds has been taken up in quantitative structure-activity relationships (QSARs see Chapter 5) as the concept of baseline toxicity and in toxicokinetics as the body burden concept (see Chapter 2). Baseline toxicity refers to the idea that a minimum toxicity expectation may be formulated for any given organic compound based on considerations of a compound s partition properties between hydrophilic and lipophilic chemicals (e.g., between water and octanol). Commonly, this is expressed in terms of the octanol-water partition coefficient (K0,J of a chemical. The partition coefficient allows estimations of a local concentration or body burden for each individual chemical in the mixture. Assuming that this produces the same toxic effect (disturbances of cell membranes), it is then possible to anticipate joint narcotic action by adding together the respective local concentrations or body burdens for each individual mixture component. 

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