Asymmetrical molar conductivity

Debye and Falkenhagen predicted that the ionic atmosphere would not be able to adopt an asymmetric configuration corresponding to a moving central ion if the ion were oscillating in response to an applied electrical field and if the frequency of the applied field were comparable to the reciprocal of the relaxation time of the ionic atmosphere. This was found to be the case at frequencies over 5 MHz where the molar conductivity approaches a value somewhat higher than A0. This increase of conductivity is caused by the disappearance of the time-of-relaxation effect, while the electrophoretic effect remains in full force. 

However, for very high frequencies of the external field, such as 10 Hz, the time for one oscillation is 10 s and this is comparable to or even smaller than the relaxation time. Under these conditions the ion is impelled backwards and forwards so rapidly that the build up of the ionic atmosphere to the asymmetric state cannot occur fast enough, and the asymmetric ionic atmosphere will not be fiiUy set up. At even higher frequencies the ionic atmosphere never has time to reach the asymmetric state and the relaxation effect totally disappears. The retarding effect of the asymmetry on the movement of the ions under the influence of the external field is removed. In consequence, the velocity of the ions and their individual ionic molar conductivities are significantly higher than for ordinary frequencies and are much nearer what would they would be expected to be if there were no retarding effect of the ionic atmosphere. 

The early conductance theories given by Debye and Hiickel in 1926, Onsager in 1927 and Fuoss and Onsager in 1932 used a model which assumed all the postulates of the Debye-Hiickel theory (see Section 10.3). The factors which have to be considered in addition are the effects of the asymmetric ionic atmosphere, i.e. relaxation and electrophoresis, and viscous drag due to the frictional effects of the solvent on the movement of an ion under an applied external field. These effects result in a decreased ionic velocity and decreased ionic molar conductivity and become greater as the concentration increases. 

In the final step chemical coupling with EDCI and DMAP was used to introduce pure EPA into the sn-2 position of adducts (S)-15a-15h to afford the asymmetrically structured MLM type TAG final products (S)-16a-16h in high to excellent yields (78-92%) after purification using silica gel chromatography. This can be noticed from Table 24.4 also showing the specific rotation for each product. The reaction was conducted in dichloromethane at room temperature for 12-15 hours. Stoichiometric amount of EPA was used, 20% molar excess of EDCI and 0.4 equivalents of DMAP. As previously observed, no acyl migration took place during this reaction. 

Figure 1 shows the relationship between a and the molar ratio of internal donor to Ti (iD/Ti) in the solid catalyst, while Figures 2 and 3 show the relationship between o and iD/Ti in the solid catalyst. In both cases the results are included where the polymerization was conducted with and without the external donor. Regardless of the presence of external donor, the value of a became larger along with the increase in the iD/Ti. a also increased as the Si/Ti in polymerization increases. This means that a, the probability of the selection of d (I) monad in the asymmetric Bemoullian site, is attributed to both the amount of internal donor of catalyst component and the amount of external donor during polymerization relative of active centers (Ti). 

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