Partition coefficient of compound

O. Dugstad, T. Bjomstad, and I. Hundere. Measurements and appliea-tion of partition coefficients of compounds suitable for tracing gas injected into oil reservoirs. Rev Inst Franc Petrol, 47(2) 205-215, March-April 1992. 

In the right part of Figure 7.1, the maximal minimal partition coefficient is found in O,. Here, the composition where the ratio of the partition coefficients of compounds i and j reaches its optimum, Oo, is also the composition that gives a robust selectivity. Optima with respect to maximal partition coefficients of both compounds are obtained with different compositions. The response surfaces are not completely parallel. Little variation in the composition of the extraction liquid does influence... 

Generally speaking, it can be said that the algorithms developed and tested here, give good approximations of the variances of the partition coefficients of compounds and of selectivities estimated with models obtained from mixture experimental designs. 

Third, the stationary phase should permit separate elution of the substances into the mobile phase and the selectivity toward samples of interest has to be sufficient to lead to separations with good resolution. The selectivity of solvent systems can be estimated by determination of the partition coefficients for each substance. The batch partition coefficients D are calculated as the ratio of the component concentration in the organic phase to that in the aqueous phase. The dynamic partition coefficients of compounds are determined from an experimental elution curve [7]. Several solvent systems for organic separation were investigated [4-8]. The most efficient evolution usually occurs when the value of the partition coefficient is equal 1. However, in some CCC schemes, the best results are obtained with lower partition coefficient values ofO.3-0.5 [1,4]. 

Sorbent extraction Sorbent extraction makes use of the differential distribution of the dissolved compounds between the solid sorbent and water. The use of organic porous polymers is advantageous for the extraction of organic compounds from water because (1) the partition coefficients of compounds in a polymer-water system reach infinity if the correct polymer is selected for the types of contaminants present (2) adsorption of water itself on the polymer is minimal (3) the wettability of the polymer with water makes possible satisfactory transport of the substance toward the polymer surface and (4) the polymer is inert. 

Unfortunately, the current costs in computer time of these simulations limit their utility as a standard tool for predicting partition coefficients of compounds of interest in drug design. 

Tewari YB, Miller MM, Wasik SP, et al. 1982. Aqueous solubility and octanol/water partition coefficient of organic compounds at 25.0°C. J Chem Eng Data 27 451-454. 

Sangster, J. Octanol-water partition coefficients of simple organic compounds./. Phys. Chem. Ref. Data 1989, 18.1111-1229. 

L. A. Predicfion of the solubility, activity coefficient and liquid/liquid partition coefficient of organic compounds. QSAR Comb. Sci. 2004, 23, 709-720. 

Fig. 16.3 ionization scheme of niflumic acid (CAS-RN 4394-00-7). The macro- (pfCJ and microprotonation (p(t ) schemes of the compound are shown. The logP value is determined by partition of neutral species (dubbed as NO) only. The microconstants and partition coefficients of each microspecies as well as the nature and the concentration of... 

A measurement table is different from a contingency table. The latter results from counting the number of objects that belong simultaneously to various categories of two measurements (e.g. molar refractivity and partition coefficient of chemical compounds). It is also called a two-way table or cross-tabulation, as the total number of objects is split up in two ways according to the two measurements that are crossed with one another. The analysis of contingency tables is dealt with specifically in Chapter 32. 

When both the neutral and the n different charged forms of a compound partition into the organic phase, a minimum of n + 1) titrations with different phase volume ratios is necessary to determine the partition coefficient of each species. For a monoprotic substance, for instance, can be related to pK by an empirical equation [119] ... 

The partition coefficient of the neutral species can then be deduced from the pH-shift between pK and pK eff, but no reliable value can be obtained with poorly lipophilic compounds because pK ff corresponds to pK in this case (see Fig. 10 for the case of methyl orange). 

V. Gobry, F. Re5miond and H. H. Girault, Refinment of Ionic Partition Diagrams and Determination of Partition Coefficients of Multiprotic Compounds by Electrochemistry at the Interface between Two Immiscible Electrolyte Solutions, submitted. 

Two hypotheses have been proposed to explain how phenolic acids directly increase membrane permeability. The first is that the compounds solubilize into cellular membranes, and thus cause a "loosening" of the membrane structure so that minerals can leak across the membrane (28-30, 42). Support for this hypothesis comes from the fact that the extent of inhibition of electrical potentials correlates with the log P (partition coefficient of a compound between octanol and water) for various benzoic and cinnamic acid derivatives (Figure 5). 

Krikorian SE, Chom TA, King JW. 1987. Determination of octanol/water partition coefficients of certain organophosphorus compounds using high-performance liquid chromatography. Quant Struct-Act Relat 6(2) 65-69. 

Partition coefficients between water and an alkanol (e.g., octanol) should be determined in preformulation programs [26]. The partition coefficient of a compound that exists as a monomer in two solvents is given by... 

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