Supplements to the procedure for tensimetric data processing

Equilibria in ion exchanger-aqueous salt solution systems and clathrate formation

“…Our approach to adjustment of the technique consists in rejecting the two above-mentioned restrictions and performing the analysis of the ion-exchange equilibrium data obtained, as well as of the possible consequences of "clathration" in solution (in the general case, Bu 4 N + binding into any other, along with Bu 4 N + solv , species [14][15][16]) and any other effects (e.g., secondary medium effects [15] both in an aqueous solution and in the "ion-exchanger phase", or "clathration" in the ion exchanger) in terms of the experimentally detected variabilities in the apparent ion-exchange equilibrium constants:…”

“…(1) the stoichiometric formula of the Bu 4 N + cation is bracketed and supplied with the superscript "*" in order to emphasize the facts that, first, this is a gross-reactant formed in an aqueous salt solution by the gross-component Bu 4 N + [16], and, second, that this conditional reactant at a higher level of elaboration [14][15][16] can be represented as two species (Bu 4 N + solv and Bu 4 NBr solv ). Based on the isothermal functions S(Bu 4 N + ) = φ t [L(Bu 4 N + )] 4 which were fairly correctly 2 Calculation of α * (Bu 4 N + ) in the framework of the model [28,29] had brought the researchers in [27] to a conclusion that clathrates can be formed in the solutions studied already at 50°C and below, but the objectively existing opportunity to verify the restrictions underlying the calculation had escaped their attention.…”

“…Hence, the question of presence/absence of significant clathration in solution is in fact still open, and the abovementioned conclusion was wrong, as will be shown below. 3 Naturally, in the adjustment we placed the focus only on provision of experimentally verifiable identifiability of the (p, T, X)-conditions (p = 1 atm, X is the vector of the composition of the aqueous salt solution in terms of the initial components [14][15][16] obtained in [27], for each temperature in the temperature series (t) examined the following conditional equilibrium constant can be associated with process (1):…”

“…Any pair of the three constants in reactions (3)-(5), as being fixed parameters 5 of the model considered, can be easily incorporated into Eq. (2) basing on the law of mass action for equilibria (3)-(5) and the mass balance equation in terms of the initial and detailed components [15]. In particular, taking constants for equilibria (3) and (4), associated with particular temperature and level of the secondary medium effects both in solution and in the ion exchanger (i.e., K Ø 3 and K Ø 4 [15]), and using Eq.…”

“…Naturally, macroensembles of these moieties (with interactions not included in the stoichiometric description and collectively termed "solvation" taken into account) can be regarded as ion pairs representing one of the types of stoichiometrically and structurally characterized chemical forms (species) [14][15][16] of a substance in solution. The concept of "ion pairs" (including "contact" ion pairs) in high-concentrated aqueous salt solution chemistry goes back a long way [17], though with the sum of knowledge about the clathrate formation phenomena uncalled.…”