D- and /-Octanol

RESOLUTION OF sec.-OCTYL ALCOHOL (d/-2-OCTA-NOL) INTO ITS OPTICALLY ACTIVE COMPONENTS (d- AND f-2-OCTANOL)... 

Figure 15.11 (a) Total ion clnomatogram of a Grob test mixture obtained on an Rtx-1701 column, and (b) re-injection of the entire clnomatogram on to an Rtx-5 column. Peak identification is as follows a, 2,3-butanediol b, decane c, undecane d, 1-octanol e, nonanal f, 2,6-dimethylphenol g, 2-ethylhexanoic acid h, 2,6-dimethylaniline i, decanoic acid methyl ester ], dicyclohexylamine k, undecanoic acid, methyl ester 1, dodecanoic acid, methyl ester. Adapted from Journal of High Resolution Chromatography, 21, M. J. Tomlinson and C. L. Wilkins, Evaluation of a semi-automated multidimensional gas chromatography-infrared-mass specti ometry system for initant analysis , pp. 347-354, 1998, with permission from Wiley-VCH. 

For the separation of D,L-leucine, Ding et al. [62] used poly(vinyl alcohol) gel-coated microporous polypropylene hollow fibers (Fig. 5-11). An octanol phase containing the chiral selector (A-n-dodecyl-L-hydroxyproline) is flowing countercur-rently with an aqueous phase. The gel in the pores of the membrane permits diffusion of the leucine molecules, but prevents convection of the aqueous and octanol phase. At a proper selection of the flow ratios it is possible to achieve almost complete resolution of the D,L-leucine (Fig. 5-12). 

Fig. 2.6 Trendships between percentage human PPB (hPPB%) and octanol-water log D " [20]. Note the around 2 log units downshift of the sigmoidal relationship for acids as compared to neutrals and basics. (With kind permission of Springer-Kluwer.)...

Livingstone, D. J., Ford, M. G., Huuskonen, J. J., Salt, D. W. Simultaneous prediction of aqueous solubility and octanol/water partition coefficient based on descriptors derived from molecular structure. J. Comput.-Aided Mol. Des. 2001, 15, 741-752. 

Valko et al. [37] developed a fast-gradient RP-HPLC method for the determination of a chromatographic hydrophobicity index (CHI). An octadecylsilane (ODS) column and 50 mM aqueous ammonium acetate (pH 7.4) mobile phase with acetonitrile as an organic modifier (0-100%) were used. The system calibration and quality control were performed periodically by measuring retention for 10 standards unionized at pH 7.4. The CHI could then be used as an independent measure of hydrophobicity. In addition, its correlation with linear free-energy parameters explained some molecular descriptors, including H-bond basicity/ acidity and dipolarity/polarizability. It is noted [27] that there are significant differences between CHI values and octanol-water log D values. 

Determined after hydrolysis to give the acid and esterification with d-2-octanol b Determined after transesterification with <7-2-octanol/Ti(0-n-Bu)4. 

Mackay, D., Bobra, A. M., Shiu, W.-Y., Yalkowsky, S. H. (1980) Relationships between aqueous solubility and octanol-water partition coefficient. Chemosphere 9, 701-711. 

Shiu, W.-Y., Mackay, D. (1986) A critical review of aqueous solubilities, vapor pressures, Henry s law constants, and octanol-water partition coefficients of the polychlorinated biphenyls. J. Phys. Chem. Ref. Data 15, 911-929. 

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. 

Using a pPLC system, log P for one unknown compound was determined in less than 1 hr. It is important to note that the excess capacity provided by the system (24 columns are available for simultaneous analysis) allows simultaneous determination of log P for six additional compounds. The same study required 5 hr using conventional HPLC, and consumed 300 mL of solvent, equivalent to 15 times the volume of solvent used for the evaluations via jtiPLC. A similar approach can be used to evaluate log D, the octanol-water distribution coefficient—a measure of the distribution ratios of all combinations (ionized and unionized) of octanol and pH-buffered water. 

Basak, S. C., Gute, B. D., and Grunwald, G. D. A comparative study of topological and geometrical parameters in estimating normal boiling point and octanol-water partition coefficient. J. Chem. Inf. Comput. Sci. 1996, 36, 1054—1060. 

Staikova, M., Wania, F., Donaldson, D. J. Molecular polarizability as a single-parameter predictor of vapour pressures and octanol-air partitioning coefficients of non-polar compounds A priori approach and results. Atmos. Environ. 2004, 38, 213-225. 

Toropov AA, Leszczynska D, Leszczynski J (2007b) Predicting water solubility and octanol water partition coefficient for carbon nanotubes based on the chiral vector Comp. Biol. Chem. 31 127-128. 

Burkhard, L.P. and Kuehl, D.W. -Octanol/water partition coefficients by reverse phase liquid chromatography/mass spectrometry for eight tetrachlorinated planar molecules, Chemosphere, 15(2) 163-167, 1986. 

Lun, R.. Shin, W. Y., and Mackay, D. Aqueous solubilities and octanol-water partition coefficients of chloroveratroles and chloroanisoles, J. Chem. Eng. Data, 40(4) 959-962, 1995. 

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