Selective solvation. Resolvation

When component B is added to solution E in solvent A (E is neutral molecule or ion), resolvation process takes plaee  

Equilibrium constant of this process in ideal solution (in molar parts of the components) equals to  

On the other hand, resolvation eonstant K s equals to the ratio of equilibrium constants of solvation processes E -i- pA EAp(I) E -l- qB EBq(II)  

The method of determination, based on the differenees between free energy values of eleefrolyte transfer from some standard solvent to A and B, respeetively, leads to a high error. 

If the eoneentration ratio of different solvative forms is expressed as a, the eoneentra-tions A and B are expressed as 1 -Xg and Xg, respeetively, (xg - molar part B), equation [9.91] may be presented in the form  

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In this chapter, we review the achievements in the area of extractions with boron extractants accomplished in the last five years. The literature on extraction with cobalt bis(dicarbollide) and synergist, the UNEX process, and new boron-selective extractants is ample, and other connected science, such as ion-selective electrodes with boron anions, boron anion room-temperature ionic liquids, modeling of the mechanism of the extraction, IR studies on extracts, the state of CD in water solutions, or a description of some of the new ideas on solvation, resolvation theory, and so on, could not be covered here. 

The data on selective solvation of 3-aminophthalimide by butanol from butanol-hexane mixture are presented in Figure 8.1.11. The data have been calculated from the equations presented above. Alcohol content in solvate shell has higher concentration than in solvent composition even at low concentration of alcohol in the solvent. For example, when molar fraction of n-butanol in the mixture was 7%, the relative molar fraction of n-butanol in the solvate shell of ami-nophthalimide was 30%. Resolvation process completes at n-butanol concentration in solution 90%. 

Solvation energy of proton by donor solvents is very high. The regularities of the proton selective solvation and resolvation processes were studied in more detail in comparison with other ions. 

Pedersen and Frensdorff studied the binding and extraction of the cation by crown ethers, which require coextraction of an anion. Without the presence of an anion host, solvation directs selectivity, giving rise to Hofmeister bias selectivity favoring low anion charge density. Anions initially in aqueous solution must be dehydrated (at least partially) and are then resolvated in the solvent phase. Empirically, the HBD ability of the solvent medium is the single most important determinant of the solvation of small, inorganic anions.100... 

A time-resolved fluorescence measurement collects the emission spectra at regular time intervals after the excitation, defined at t=0, from which one constructs the normalized solvation dynamics response function, S(t) = [hv(t)—hv(oo)]/[hv(0)— hv(oo)] [55], In our simulations, hundreds of uncorrelated equilibrium molecular configurations with the electron in its ground state were selected as initial configurations (t=0). From each of these initial configurations, the electronic state is adiabatically promoted to the first excited state, the system is then propagated in... 

In this latter structure, roughly depicted as (154), there are two different lithium atoms as well as two different anion residues. In one of the residues a lithium is -coordinated and in the other residue the lithium is T) -coordinated. Hie possible origins of the selectivity of the alkylations of the metallated hydiazones are discussed relative to this structure. Hie lithiated hydrazone enolate (155) prepared from (S)-(-)-l-amino-2-(methoxymethyl)pyrrolidine (SAMP) hydrazone of 2-acetylnaphthalene (156) yields the monomeric bis-THF-solvated species (157) as ruby red crystals. Hiis is one of the few examples of the crystallization of a resolved enolate substrate. ... 

How far carbocation chemistry has evolved from the old solvolysis days is demonstrated by two recent stmcture determinations the IR spectrum of the nonclassical CHs cation has been measured by solvating this unusual species with molecular hydrogen in the gas phase. This slows down the ultrafast fluxional process which so far prevented the recording of vibrational spectra. The cluster ions CH5" (H2)n (n = 1, 2, 3), after mass selection by an ion trap, were then subjected to IR laser spectroscopy/quadrupol mass spectrometry which ultimately yielded the IR absorption. [40] And the benzene cation, formed by removal of one electron from the parent hydrocarbon was shown to possess Deh symmetry by rotation resolved ZEKE-photoelec-tron spectroscopy (Zero Tinetic Energy-PES). [41]... 

A similar approach has been developed for calculation of solvate shell composition Na and F in the mixed solvent formed by the components with close values of permittivity. Such solvent selection permits us to eliminate the permittivity effect on solvation equilibrium. Resolvation constants have been determined from the calorimetric study. The composition of anions solvate complex has been determined from experimental data of electrolyte BU4NI assuming lack of the cation specific solvation. Experimental data are presented in Figure 9.10. 

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