Structure of Octanol

The aliphatic tails form a hydrocarbon region with properties not too different from the hydrocarbon core of bilayers. The clusters have an interfacial zone 

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The flic presented contains 11 data items. The header lines arc property names as used by CACTVS [64, 65], and arc sufficiently self-descriptive. For example, E NHDONORS is the number of hydrogen bond donor.s, E SM1LES" is the SMILES string representing the structure of sulfamidc, and E LOGP is the logP value (octanol/water partition coefficient) for this substance. 

On the basis of data obtained the possibility of substrates distribution and their D-values prediction using the regressions which consider the hydrophobicity and stmcture of amines was investigated. The hydrophobicity of amines was estimated by the distribution coefficient value in the water-octanole system (Ig P). The molecular structure of aromatic amines was characterized by the first-order molecular connectivity indexes ( x)- H was shown the independent and cooperative influence of the Ig P and parameters of amines on their distribution. Evidently, this fact demonstrates the host-guest phenomenon which is inherent to the organized media. The obtained in the research data were used for optimization of the conditions of micellar-extraction preconcentrating of metal ions with amines into the NS-rich phase with the following determination by atomic-absorption method. 

Then there are a number of pesticides, e.g. the phenolic herbicide dinoseb and the fungicide pentachlorophenol, whose speciation varies strongly in the environmental pH-range. For this reason, one has to consider the pwhen estimating their environmental fate. Structures of the compounds discussed in this section are depicted in Table 1, together with a listing of their pand octanol-water partition coefficients, Kow, of the neutral species (unless otherwise indicated). Typical basic pollutants include the industrial chemicals aniline and jV.jV-dimethylaniline. 

The octanol-water partition coefficient, Kow, is the most widely used descriptor of hydrophobicity in quantitative structure activity relationships (QSAR), which are used to describe sorption to organic matter, soil, and sediments [15], bioaccumulation [104], and toxicity [105 107J. Octanol is an amphiphilic bulk solvent with a molar volume of 0.12 dm3 mol when saturated with water. In the octanol-water system, octanol contains 2.3 mol dm 3 of water (one molecule of water per four molecules of octanol) and water is saturated with 4.5 x 10-3 mol dm 3 octanol. Octanol is more suitable than any other solvent system (for) mimicking biological membranes and organic matter properties, because it contains an aliphatic alkyl chain for pure van der Waals interactions plus the alcohol group, which can act as a hydrogen donor and acceptor. 

In addition, the steric bulk of several substituents on an amino group appears to disturb the structure of the membrane more than a single substituent. Amw for a series of (/>-mcthylbcnzyl)alkylamincs increase with increasing alkyl chain length [153]. This trend was not observed for the corresponding octanol-water partition data, which is additional evidence that the increase in Amw is caused by an unfavourable steric constraint. The positively charged... 

The octanol/buffer represents a partition coefficient between two bulk phases it is less affected by the structure of the analyte and therefore it cannot be used to predict the exact value of liposome membrane-to-buffer Xp, which is also affected by the geometry of the analyte (41 4). However, it is accepted and established that the octanol-to-buffer can help to predict transmembrane passive diffusion (40). In the case of liposomes such as Doxil, in which the internal aqueous phase (intraliposome aqueous phase) is different from the external liposome aqueous medium due to large differences in the composition and pH of these two aqueous phases, there are two different liposome membrane-to-aqueous phase partition coefficients this is referred to as asymmetry in the membrane-to-aqueous media partition coefficient. 

Figure 6.13 shows the concentrations of organic compounds in water that are sufficient to immobilize tadpoles, and their values of log P or the partition coefficient between octanol and water. Thymol, with a log P of 1000, is 10,000 times more toxic than ethanol, which has a log P of around 0.3. A plausible explanation of this phenomenon lies in the structure of the membranes of cells, which are made of two layers of lipid, or fat, so that a more fat-soluble substance would find it easier to penetrate the cell and to cause damage. 

The bis(2-ethylhexyl) sodium sulfosuccinate system was initially investigated because its structure of liquid crystalline solution phases and mechanism of solubilization with water had been reported by Rogers and Winsor (10). In our studies, we substituted methanol for water. Table I lists critical micelle concentrations for bis(2-ethylhexyl) sodium sulfosuccinate, triethylammonium linoleate and tetradecyldimethylammonium linoleate in methanol and 2-octanol at 25°C. Literature references for critical micelle concentrations in methanol are sparse, and it has even been suggested that in polar solvents such as ethanol, either micellization does not occur or, if it does, only to a small degree (4). The data of Table I show that micellization occurs in methanol at low concentrations. 

Fig. 15.7. a Chemical structures of vitamin E (a-TH) and vitamin E acetate (a-TAc) as indicated, b Confocal Raman spectra of skin after topical application of 60% a-TAc in octanol were acquired every 2 pm to an overall depth of 60 pm. The first 15 spectra of skin in the 450-1050 cm-1 range are shown, c Raman spectra of the 400-700 cm-1 region for pure vitamin E (a-TH) and pure vitamin E acetate (a-TAc) as marked... 

The new features are detailed in this review most using diamide as a model system and illustrated with published data on other extractant systems. Figure 7.1 summarizes the structure of the different extractants cited in this chapter. The mixture of extractants as synergistic systems and extractants, such as the N-polydentate ligands BTP (39, 40), BTBP (41, 42), or bis-malonamide (43), will not be treated here. These extractants have low solubility in alkane and are generally used in chlorinated solvent or octanol or diamide/alkane solution to enhance their solubility. 

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