Medium effects through

The commercial product, m.p. 53-55°, may be used. Alternatively the methyl -naphthyl ketone may be prepared from naphthalene as described in Section IV,136. The Friedel - Crafts reaction in nitrobenzene solution yields about 90 per cent, of the p-ketone and 10 per cent, of the a-ketone in carbon disulphide solution at — 15°, the proportions ore 65 per cent, of the a- and 35 per cent, of the p-isomer. With chlorobenzene ns the reaction medium, a high proportion of the a-ketone is also formed. Separation of the liquid a-isomer from the solid p-isomer in Such mixtures (which remain liquid at the ordinary temp>erature) is readily effected through the picrates the picrate of the liquid a-aceto compound is less soluble and the higher melting. 

Because of the uncertainties related to the parametrization of an sp C, this approach is unsuitable for the study of protomeric equilibria for structures 4 through 8. We must lay stress on the fact that this simple treatment does not include (a) medium effects which are known to be important and b) the existence of associated species (see Chapter VII, Section I. LB) whose consequences have been thoroughly studied in pyridone series (1688). 

In addition, medium effects play an important role through the interaction of solvent molecules with p and a as well as with each other thus the two partners should present geometrically matched hydrophobic/hydrophobic or hydrophilic/hydro-philic (solvophobic, solvophilic, more generally) domains. 

The salt is essentially operating through a medium effect and in this experiment we have a particularly dramatic salt effect in which the free energy barrier for the assembly reaction is systematically decreased as the salt concentration is increased. As the temperature is lowered, it is found that the rate of the self-assembly reaction increases. This can be understood from considerations of Fig. 19.7. As the temperature is lowered, the esc decreases, so if the salt concentration is kept constant, there will be a... 

Electrophoretic effect — A moving ion driven by an electric field in a viscous medium (e.g., an electrolyte solution) is influenced in its movement by the - relaxation effect and the electrophoretic effect. The latter effect is caused by the countermovement of ions of opposite charge and their solvation clouds. Thus an ion is not moving through a stagnant medium but through a medium which is moving opposite to its own direction. This slows down ionic movement. See also -> Debye-... 

Medium effects can be divided into two classes those that directly modify the potential energy surfaces of the molecule, such as polarity or hydrogen bonding capacity, affecting through strong solvation in particular the (n,ji ) as opposed to the ( r, r ) state energies, and those that operate in a more subtle manner. Examples of the latter are microscopic heat conductivity. 

---