Cations C

Figure 9.1. 395 MHz M NMR spectra of 2-iiorbornyl 50 MHz proton decoupled C NMR spectra cation in SbF5/S02CIF/S02F2 solution of 2-norbornyl cation ( C enriched) in SbF5/S02ClF/S02F2 solution.

Examples of the application of ion-exchange chromatography to the analysis of (a) inorganic anions, (b) inorganic cations, (c) antifreeze, and (d) vitamins. (Chromatograms courtesy of Alltech Associates, Inc. Deerfield, IL). 

If the experimental conditions are such that the equilibrium is completely displaced from left to right the cation C+ is completely fixed on the cation exchanger. If the solution contains several cations (C+, D+, and E + ) the exchanger may show different affinities for them, thus making separations possible. A typical example is the displacement of sodium ions in a sulphonate resin by calcium ions ... 

Such an electrode may, however, also show a response to certain other singly charged cations, and when an interfering cation C + is present in the test solution, an equilibrium is established between ions M + in the glass surface in contact with the solution, and the ions C + in the solution ... 

Conductivity curves (A versus c ) of salts in solvents of low-permittivity commonly show a weakly temperature-dependent minimum around 0.02 molL-1 followed by a strongly temperature-dependent maximum at about 1 mol L 1. According to Fuoss and Kraus [101,102] the increase of conductivity behind the minimum is due to the formation of new charge carriers from the ion pairs. They assume that coulombic forces suffice to form bilateral cationic [C+A-C+] and anionic [A C+A ] triple ions in solvents of low-permittivity ( <15) if the ions have approximately equal radii. 

Figure 4. Schematic representation of separating motion of cation C from the reference ion A. A is another anion of the same kind, and C, plays a role of tranquilizer if the interaction of A -Ct is much stronger than that of A -C.

Fig. 6.2 Concentration distribution of cations c+, anions c and fixed anions in a cationexchanging membrane. The bathing solutions have electrolyte concentrations cx and c2. (According to K. Sollner)...

The importance of alkali metal binding with available 7r-electron density in the formation of CIPs was also demonstrated by Niemeyer in the structural elucidation of the first monomeric non-solvated lithium cuprate, [(2,6-Mcs2(LI L)2CuLi] 450, formed from the reaction of 2 equiv. of (2,6-Mcs2Gf,I L)Li with /-BuOCu in pentane.447 The complex crystallizes as two different independent molecules in which the C-Cu-C angles differ (171.1° and 173.8°) as does the mode of coordination to the Li cations C pso and rf to one pendant Ph in molecule 1, with an additional rf interaction to a second Ph group in molecule 2. In the second molecule, the Li site is 10% occupied by a Cu ion. 

However, the character of the reaction of 3-nitro-substituted TV-oxide (169) with the C,C triple bond is changed 371. Apparently, the first step affords the normal cycloadduct A, which is successively rearranged into aziridine B. Elimination of the nitronate anion from the latter compound gives rise to ambident cations C and D, which, after quenching with methanol, form dihydrooxazines (170) or (171) depending on the nature of the substituent R. 

Fig. 1.7. Mapping of anionic (A) and cationic (C) states in zazs-plane for rf = 1. Reprinted from Grimley (1960) with permission from Elsevier.

The magnitude of c is more difficult to determine. In most studies of cationic polymerizations the nominal catalyst concentration lies in the range 10 2-10 4 mole/l. However, in syncatalytic systems, such as SnCl4-H20, the total concentration of cations, c, at any instant may be equal to the concentration of the scarcer of the two components (usually 10 3 to 10"5 mole/l) or it may be very much less than this. 

Here m is the molality of cation c with charge z and correspondingly for anion a. Sums over c or a cover all cations or anions, respectively. B s and 0 s are measurable combinations of A s whereas C s and 0 s are combinations of the u s in Equation (3). Note that the 0 s and 0 s are zero and these terms disappear for pure electrolytes. 

Metrosep Cation C 1 Metrohm 2-7 70 Moderate WCX PES Maleic Tartrate/ PDCA oo 0... 

Metrosep Cation C 2 Metrohm 2-7 100 Moderate WCX PES Silane Tartrate/ PDCA 8 z... 

A good general-purpose weak acid cation-exchange column for non-suppressed applications is the Metrosep Cation C 2 column from Metrohm. As the selection of eluents used with this column is quite varied, the reader is referred to Metrohm column literature for specific eluent recommendations. The Metrosep Cation C 2 column is prepared via encapsulation of a porous silica substrate maliec acid copolymer. 

The standard molar Gibbs energy of transfer of CA is the sum v AG°(C) -i-v AtG°(A), where the charges of the cation C and anion A " and the designation of the direction of transfer, (aq org), have been omitted. The values for the cation and anion may be obtained from tables [5-7], which generally deal with solvents org that are miscible with water and not with those used in solvent extraction. However, AtG°(C) depends primarily on the (3 solvatochromic parameter of the solvent and AtG°(A) on its a parameter, and these can be estimated from family relationships also for the latter kind of solvents. 

Aqueous cation C and anion A) associated into ion pair C Aj... 

Figure 4. Activity coefficients of cations relative to the tetraethylammonium cation in sulphuric acid-water mixtures. A—anilinium ions 1, unsubstituted 2, J5-C1 3, P-NO2 4, m-N02. B—benzamide cation. C—a typical carbonium ion, (p-MeOCgHajsC. A and C, after Boyd, 1963 B, after Sweeting and Yates, 1966.

Because the conventional standard partial molal properties of a hydrogen ion is zero, it follows that the conventional standard partial molal properties of a generic anion A are identical to the experimental values of the corresponding acid electrolyte. Moreover, based on equation 8.104, the standard partial molal properties of a generic cation C can be calculated, once the experimental values for aqueous electrolytes H +A and are... 

The studies of naphthalene and bromonaphthalene ions are companion studies in that they both access the thermochemistry of the naphthyl cation, C, oH, using a combination of TRPD energy-specific rate measurements with deconvoluted time-resolved photodissociation (TPIMS) results [Equations (12) and (13)]. In this... 

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