Solvents aggregation

Eicke, F. H. Surfactants in Nonpolar Solvents. Aggregation and Micellization, in Topics in Current Chemistry (ed. Boschke, F. L.), p. 85, Berlin—Heidelberg—New York, Springer 1980... 

Eicke, H.-F. Surfactants in Nonpolar Solvents. Aggregation and MiceUization. 87, 85-145 (1980). 

H. F. Eicke. Surfactants in nonpolar solvents. Aggregation and micellization. Topics Curr. Chem., 87 85-145, 1980. 

Arenes cannot usually be deprotonated with LDA alone, but require mixtures of organosodium [365] or organolithium compounds and tertiary amines [181, 218, 219]. These amines, for instance TMEDA, lead to a partial dissociation of oligomeric BuLi-solvent aggregates and thereby to more powerful metalating reagents [366, 367]. Thus, although benzene cannot be deprotonated with BuLi alone, a mixture of BuLi and TMEDA leads to quantitative lithiation [181]. 

Berkessel A, Adrio JA, Ffiittenhain D, Neudorfl JM (2006) Unveiling the booster effect of fluorinated alcohol solvents aggregation-induced conformational changes and cooperatively enhanced Fl-bonding. J Am Chem Soc 128 8421-8426... 

Berkessel A, Adrio JA (2004) Kinetic studies of olefin epoxidation with hydrogen peroxide in l,l,l,3,3,3-hexafluoro-2-propanol reveal a crucial catalytic role for solvent clusters. Adv Synth Catal 346 275-280 Berkessel A, Adrio JA (2006) Dramatic acceleration of olefin epoxidation in fluorinated alcohols activation of hydrogen peroxide by multiple H-bond networks. J Am Chem Soc 128 13412-13420 Berkessel A, Adrio JA, Huttenhain D, Neudorfl JM (2006a) Unveiling the booster effect of fluorinated alcohol solvents aggregation-induced conformational changes, and cooperatively enhanced H-bonding. J Am Chem Soc 128 8421-8426... 

Now that some methods for investigating the structure of the ion-solvent complex in solution have been described, it is time to learn systematically what is known about it. One can start by considering systems that avoid the complexity of liquid water. By varying the partial pressure of water vapor while keeping it low (0.1-lOkPa), it is possible to find the equilibrium constant between water vapor and the entities represented by a number of ion-solvent aggregates, M(H20), in the gas phase (Kebarle and GodMe, 1968). 

Ionic Equilibria and Their Effect on the Permittivity of Electrolyte Solutions. Most of the commonly used solvents exhibit several relaxation processes that show up in the change of dielectric constant with frequency (see Section 2.12). These relaxation processes include rotation and libration of the molecules of the solvents, aggregates of ionic species, and H-bonding dynamics. 

The results listed in Tables 1 and 2 also indicate that the sizes of the solvent aggregates predicted from the BN and ML excesses are in agreement with those evaluated from the large negative partial molar volume of the solute at infinite dilution. However, as already noted the BN excesses provide unreasonable results for the aggregate sizes in mixtures far from the... 

In summary, the infrared spectra of aprotic solvents are much simpler than those of protic solvents because of the absence of complications due to hydrogen bonding. On the other hand, the aprotic liquids are characterized by very high molecular dipole moments. As a result, dimers can be formed in which some of the molecules line up with their dipole vectors in an antiparallel fashion [30]. This can lead to the spectra being complicated by additional spectral features due to solvent aggregates. Nevertheless, the prominent band due to the polar group in these solvents can be used to probe solute-solvent interactions in non-aqueous media. This subject is discussed in more detail in the next section. 

Solvent (aggregated) -I- heat-> solvent (separated) A//soivem > 0... 

Antigens formulations Experimental conditions Reconstituting solvent Aggregate solubility (%) (Average S.D., n = 3) Aggregation mechanism... 

Stabilized dispersion in organic solvent Aggregates, sometimes monodis-persed spherical beads Low Mature technology, scalable to large batches Very sensitive to experimental conditions, aggregates poorly suitable for chromatography... 

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