Octanol nonaqueous phase

Today, lipophilicity can be determined in many systems that are classified by the characteristics of the nonaqueous phase. When the second phase is an organic solvent (e.g. n-octanol), the system is isotropic, when the second phase is a suspension (e.g. liposomes), it is anisotropic, and when the second phase is a stationary phase in liquid chromatography, it is an anisotropic chromatographic system [6]. Here, we discuss the main aspects of isotropic and anisotropic lipophilicity and their biological relevance the chromatographic approaches are investigated in the following chapter by Martel et al. 

Octanol is often used as the nonaqueous phase in experiments to measure the partition coefficient of dmgs. Its polarity means that water is solubilised to some extent in the... 

On the industrial level, aqueous two-phase systems are used more often than nonaqueous two-phase systems. The Kuraray Co. operates a pilot plant for the hydrodimerization of 1,3-butadiene in a two-phase system with a Pd/tppms catalyst (140). The reaction is carried out in sulfolane-water, from which the products, the octadienols, separate. The final products can be octanol or nonanediol made by subsequent isomerization and hydroformylation. The capacity of the Kuraray process is about 5000 tons/year. 

Lipophilicity is frequently used in QSAR analysis and expressed as the partition coefficient P (or by its decimal logarithm, log P) between a nonaqueous and aqueous phase. Another parameter, which takes into account the equilibrium of an ionizable compound at a stated pH value, is the distribution coefficient (Z>), which depends on the P of the single species and on the pAT values of the chosen compound. P and D have been evaluated for different N-substituted l,2-benzisothiazol-3-one derivatives using the partition between -octanol and water. Selected data are reported in Table 9 <1996FES493, 2002EJM553>. 

Oxidations with dichromates can be accomplished in nonaqueous media or in a two-phase system by using phase-transfer reagents. The addition of 1-phenylethanol to a slurry of potassium dichromate and Adogen 464 (methyltrialkylammonium chloride) in benzene heated at 55 °C for 15 h results in an 80% yield of acetophenone. However, 2-octanol gives only a 33% yield of the ketone after being heated at 55 °C for 24 h [651]. Other solvents suitable for the reaction are dichloromethane, chloroform, and carbon tetrachloride, but not hexane [651], Better results are obtained when the alcohol is shaken for 1 min at room temperature with a mixture of a catalytic amount (10%) of tetrabutylammonium bisulfate and sodium dichromate in dichloromethane and aqueous 3 M sulfuric acid [630. ... 

The application of UNIFAC to the solid-liquid equilibrium of sohds, such as naphthalene and anthracene, in nonaqueous mixed solvents provided quite accurate results [11]. Unfortunately, the accuracy of UNIFAC regarding the solubility of solids in aqueous solutions is low [7-9]. Large deviations from the experimental activity coefficients at infinite dilution and the experimental octanol/water partition coefficients have been reported [8,9] when the classical old version of UNIFAC interaction parameters [4] was used. To improve the prediction of the activity coefficients at infinite dilution and of the octanol/water partition coefficients of environmentally significant substances, special ad hoc sets of parameters were introduced [7-9]. The reason is that the UNIFAC parameters were determined mostly using the equihbrium properties of mixtures composed of low molecular weight molecules. Also, the UNIFAC method cannot be applied to the phase equilibrium in systems containing... 

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