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Alkanes general appearance

The CF3 groups of 1,1,1-trifluoro-n-alkanes generally absorb at about -68 ppm, as typified by 1,1,1-trifluorohexane and 1,1,1-trifluorooctane, which are reported to absorb at -67.8 and -67.7 ppm, respectively, each appearing as a triplet with a Vpn = 11 Hz. As can be seen in Scheme 5.1, branching provides additional shielding to the CF3 fluorines. [Pg.189]

The primary steps in the oxidation of iso- and cyclo-alkanes are probably the same as in the case of -alkanes. However, the number, size and arrangement of side chains at the alkane molecule appear to have a stronger influence on the oxidation capacity. No general rules have yet been worked out, and only a few points are clear ... [Pg.173]

The general appearance of the mass spectmm depends on the type of compound analyzed. Seeing the patterns that distinguish, say, a normal alkane from an aromatic hydrocarbon. [Pg.667]

For the homologous series of alkanes, peaks at m/z = 15, 29, 43, 57, etc. will be noted starting at 15 (CH3). For other homologous series such as straight-chain alcohols or amines, the same general appearance is observed in the spectmm but the m/z values will be displaced by the difference in mass of the functional group. Table 10.14 shows the terminal group and the first several m/z peaks of such series. [Pg.671]

The general appearance of the mass spectrum depends on the type of compound analyzed. We will look first at the normal alkanes (saturated straight-chain hydrocarbons of the formula C H2 +2. also called paraffins). Figure 10.13 shows the spectra of n-C,6 and n-C Q alkanes. It can be seen that... [Pg.782]

Paraffins consist mainly of straight chain alkanes, with a very small proportion of isoalkanes and cycloalkanes. Their freezing point is generally between 30°C and 70°C, the average molecular weight being around 350. When present, aromatics appear only in trace quantities. [Pg.285]

Figures 7.31a-c clearly show that after some critical soy content in dodecane, Pe values decrease with increasing soy, for both sink and sinkless conditions. [This is not due to a neglect of membrane retention, as partly may be the case in Fig. 7.23 permeabilities here have been calculated with Eq. (7.21).] Section 7.6 discusses the Kubinyi bilinear model (Fig. 7.19d) in terms of a three-compartment system water, oil of moderate lipophilicity, and oil of high lipophilicity. Since lipo-some(phospholipid)-water partition coefficients (Chapter 5) are generally higher than alkane-water partition coefficients (Chapter 4) for drug-like molecules, soy lecithin may be assumed to be more lipophilic than dodecane. It appears that the increase in soy concentration in dodecane can be treated by the Kubinyi analysis. In the original analysis [23], two different lipid phases are selected at a fixed ratio (e.g., Fig. 7.20), and different molecules are picked over a range of lipophilicities. Figures 7.31a-c clearly show that after some critical soy content in dodecane, Pe values decrease with increasing soy, for both sink and sinkless conditions. [This is not due to a neglect of membrane retention, as partly may be the case in Fig. 7.23 permeabilities here have been calculated with Eq. (7.21).] Section 7.6 discusses the Kubinyi bilinear model (Fig. 7.19d) in terms of a three-compartment system water, oil of moderate lipophilicity, and oil of high lipophilicity. Since lipo-some(phospholipid)-water partition coefficients (Chapter 5) are generally higher than alkane-water partition coefficients (Chapter 4) for drug-like molecules, soy lecithin may be assumed to be more lipophilic than dodecane. It appears that the increase in soy concentration in dodecane can be treated by the Kubinyi analysis. In the original analysis [23], two different lipid phases are selected at a fixed ratio (e.g., Fig. 7.20), and different molecules are picked over a range of lipophilicities.
The halogenated hydrocarbons are generally of low acute toxicity, but several are associated with anesthetic effects and cardiac sensitization. Cardiac sensitization to halogenated alkanes appears related to the number of chlorine or fluorine substitutions. Halogenated alkanes in which >75% of the... [Pg.161]

The saturates boiling above 470°F were analyzed by MS and appear to contain alkanes but predominantly cycloparaffins. The alkanes appearing in these liquids may not be part of the coal network but may simply be embedded in it. The primary coal structure is generally believed to be formed of small aromatic units held together by short links, mainly... [Pg.45]


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See also in sourсe #XX -- [ Pg.33 , Pg.34 , Pg.35 ]




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