Equilibrium States in Aqueous Solutions of Some Ionic Liquids

Abstract—Physicochemical properties of aqueous solutions of a number of proton ionic liquids (electrical conductivity, dissociation parameters, pH, and concentration functions) are determined using specially designed equipment and the techniques of computer resistometry. The correlations between the physicochemical properties of water–organic mixtures and a possible structure of the organic phase are established.


INTRODUCTION
Approximately 200 works concerning ionic liquids are published every year since these liquids are widely used in new materials and technological processes [1][2][3][4][5][6]. For instance, a technological process to produce biofuel from cellulose based on the ability of 1-ethyl-3-acetate of methylimidazoline and lysinate-choline to effectively dissolve the biomass is proposed in [7]. Hybrid supermicrofiber, filled with nanocarbon, chitine, etc., is generated from cellulose processed in the ionic liquid (IL) [8]. The electrochemical polymerization method was used to synthesize the IL with an asymmetric molecular structure, such as poly(3,4ethylenedioxythiophene) spiral films consisting of helical bundles of fibrillas. On this basis, effective separator materials for modern current sources are produced [9].
Another key priority in the case of IL application is "green chemistry"-creation of new materials that provide the highest protection for the environment both in production and application. It includes the mentioned processing of cellulose as well. The IL was used to create some fuel additives that decrease the content of carbonaceous particles and volatile organic pollutants in exhaust gases [10]. The exhaust gases become less toxic, and the working time of pipeline equipment, where the fuel combustion products are deposited, is prolonged.
The porous matrix of tetraethylorthosilicate electrodes is doped with nitrogen with the help of the polyionic liquid. This technology was used to create an electrode material for electrochemical capacitors with disordered graphite layers, with a specific surface area up to 1324 m 2 g -1 and more than 2400 charge-discharge cycles [11].
Photoirradiation was used to produce the IL microgels of 2-acrylomide-2-methyl-1-propane-sulphonic acid treated with tris(dioxa-3,6-heptyl)amine [12]. The microgels were used as matrices to produce Co and Ni nanoparticles. These materials proved effective as catalysts for the hydrolysis of natrium borane to generate hydrogen (an ecologically clean energy carrier).
The ILs capable of distinguishing the substances with a structural asymmetry on the basis of imidazoline cation and radical anions of carbonyl compounds were synthesized in analytical chemistry. These ILs substitute both organic solvents and auxiliary electrolytes in the electrosynthesis [13]. Some other IL-based reagents, capable of responding to particular substances and of being indicators in the chemical analysis, were proposed [14,15].
In electrochemical systems, ILs have long been used in membrane technologies [16,17], in electrochemical current sources, and in electrochemical sensors [18].

RESEARCH TASK
The research's purposes are to measure the concentration and temperature dependences of the conductivity χ and the hydrogen ion exponent (pH) in the aqueous solutions of the proton ionic liquids and to determine the types of charge carriers and their relative contribution into electric conduction on the basis of the known theories of electric conduction and electrolytic dissociation. This fact allows us to make some conclusions concerning the correlation between the physicochemical properties of the aqueous solutions of ionic liquids and their supposed structure.
We studied the properties of a small group of proton ionic liquids (PILs) based on ammonium oligoesters-water-soluble compounds with organic cations and nonorganic anions (residues of sulphuric, orthophosphoric, and acetic acids). The investigations were performed using the computer resistometry method that was first analytically supported and described in detail in our works [19,20]. The possibility of the nonequilibrium dynamic processes was also estimated experimentally. On the basis of the integrated measurement results, we established the correlation relationships between the physicochemical properties of water-organic mixtures and the possible parameters of the structure of the organic components.
As proton ionic liquids, we studied the substances for which the structural formulas were proposed ( Fig. 1) due to the production conditions and the structure of original substances used in the synthesis process.
The ionic liquid PIL(VI) is produced due to the neutralization of monoethanolamine by acetic acid.

MEASURING TECHNIQUE
The main parameter (conductivity) was measured using computer resistometry with the help of special sensors (Fig. 2), which operate in the liquid bulk or in microvolumes up to 50 mm 3 in the flowing solutions [21]. The constants of the sensors S/L were determined measuring the resistances of the known solutions (KCl, NaCl) with different concentrations, and graphs were constructed whose shape is represented in Fig. 3. If the graph is a straight line, then the solution conductivity χ was found from the reference tables at any   (1). (1) The relationship 1/R = f(C) shown in Fig. 3 is nonlinear at the concentrations С < 0.04 M, though it is hardly seen in the figure scale. Hence, a more accurate concentration was determined in another way. The analytical value χ of the known substance can be calculated accurately using the computer program approximating the reference data, say, by polynomials to the third order: (2) The precise data concerning the conductivities of ions and salts presented in [18] are repeated in all modern reference books, textbooks, and monographs [3,8,10]. The concentration of the single-component solution C = f(χ) was determined comparing the precise calculated value and experimentally measured value of the conductivity χ. At higher concentrations, the sample was diluted to a level of С < 0.01 M, and the obtained result was recalculated with regard for the dilution.

SENSOR LOW-FREQUENCY RESISTOMETER FLC
A special sensor resistometer FLC was designed to record the dynamics of quick processes without any sample collection. The sensor gives a primary signal in the form of the solution's resistance in the working chamber. The resistance was then recalculated into the solution conductivity; thus, the apparatus can be considered a low-frequency conductivity meter (FLC). At In the electronic circuit diagram of the resistometer, the processor (ATmega328 on the ARDUINO UNO R3 board) forms a stabilized voltage of U 0 = 5 ± 0.005 V.
This voltage arrives at two separate inputs of the processor. The processor program successively forms the equal pairs of rectangular pulses with a voltage of 5 V with the opposite polarities. The pulse current flows through the voltage divider consisting of the solution resistance in the sensor chamber and the constant resistor. In the positive current pulse, the voltage drop on the resistor is measured, and the installed program calculates the resistance of the solution in the working chamber of the sensor according to its value.

EXPERIMENTAL TECHNIQUE WITH IONIC LIQUIDS
In modern literature, the term "ionic liquids" is used for organic salts in a liquid state within a wide range of temperatures. At below room temperatures, these salts have ionic conductivity [20]. The organic salts, which refer to ionic liquids and are in a molten state at room temperature, are called "Room-Temperature Ionic Liquids" (RTIL). The ionic liquids can be in a solid state in the form of powders or waxy sub-  stances. A typical property of these substances is a low melting temperature, according to some reports, not higher than 100°С. This is due to the complex structure hindering the crystallization. The compounds produced with the neutralization of organic bases by nonorganic and organic acids refer to the proton ionic liquids (PILs). If both cation and anion are strong enough in these compounds, there is most often the transfer of the proton from the acid to the base. In this case, the degree of proton transfer changes depends on the strength of the acid and base.
The ionic liquids under investigation were synthesized in the Ukrainian State University of Chemical Technology and presented for study in the concentrated form of samples with a mass as high as 2-3 g. All the samples had a body of translucent colorless and highly viscous liquids hardly soluble in water. More diluted aqueous solutions were preliminary prepared from each ionic liquid. The computer resistometry method [21,22] was then used to measure the conductivity of these solutions and its dependence on the temperature and concentration of the oligomer. The concentration dependence pH was measured simultaneously.
The first operation is the dissolution of the ionic liquid in water with the generation of a 10% and 20% solution. To prepare solutions, the components were weighed using a precise digital scale with an accuracy to 0.01 g. Initially, the test tube with the sample was heated for 3-5 min in hot water to a partial decrease in viscosity, and the precipitate was rubbed down with a glass rod until its the total disappearance. The solution was transferred into a prepared and weighed vessel, and some distilled water was added until a translucent solution with a required concentration of 10 and 20% was obtained.
The solutions to receive the concentration dependences of pH and resistance were prepared in the following way. Since the original substance itself was highly viscous, the initial solution was prepared with a concentration of 10 or 20% for a normal work. A series of diluted solutions with different concentrations were prepared using two methods. Method 1. A portion of the ionic liquid solution beginning with a concentration of 10 and 20% was successively double diluted, and the resistance and pH value were measured for each concentration. Only five solutions were prepared according to this method. Method 2. Some water was successively added to a portion of the initial 20 or 10% solution, and the total solution weight was measured using a scale. For each concentration, the resistance with the help of the FLC resistometer was determined, and both numbers were written down. Any number of solutions can be obtained according to this method, depending on the water volume added at every step.
The temperature impact on the conductivity was determined on the first most concentrated 10 or 20% solution.
The experiment at different temperatures was performed in the steel thin-walled lidded sleeve of 50 mL (Fig. 5). The sleeve was firmly fixed in a heavy holder and arranged in the inertia thermostat, which was a 4-L vessel with water. The resistance was regularly measured in the course of heating or cooling of the thermostat. When the required temperature was achieved, the heater was switched off, the temperature field was smoothed with an agitator, the thermostat was uncovered, the sensor was submerged, and the resistance was measured. In the course of measurements, the liquid was pumped in reciprocating motions for 3-5 times through the working chamber of the sensor to heat it to the solution temperature on the forward stroke (dT/dτ > 0) and to cool it on the reverse stroke (dT/dτ < 0). When a constant value of the resistance was established, it was recorded. After every measurement, the sleeve was covered to protect it from water loss through evaporation, and the heater was switched on for 3-4 min to pass to the following value of temperature.
The special structure of the flowing sensor ( Fig. 2) with a cylindrical working chamber with d = 3 mm and h = 4 mm allowed working with small solution portions 30-50 mm 3 in volume.
The sensor FLC-18 with a constant of S/L = 18.5 сm -1 was used in all the tests.

ANALYSIS OF EXPERIMENTAL DATA
Sulphate Ionic Liquids Let us consider a typical technique for analyzing the experimental results using the ionic liquids PIL(I), М = 189 g mol -1 and PIL(II), М = 272 g mol -1 as an example. The empirical function χ(С) for PIL(I) is shown in Fig. 6. It has the nonlinear shape of a parabola. The nonlinearity is associated with two reasons: (1) The nonlinearity is evidence of strong electrolytes that manifests itself as an inhibiting action of the interionic interaction in the aqueous solutions of oligomers.
(2) The nonlinearity can manifest itself as the inhibiting action of the viscous solution of the oligomer itself with hydrated molecules, which is typical for colloidal solutions. Figure 6 shows that, in the H2SO4 solutions within a similar range of the oligomer solution concentrations, the nonlinearity of the function χ(С) is barely noticeable. It follows that the nonlinearity effect in the aqueous solution PIL(I) is a result of the viscosity action, which is determined by the cation oligomer component.
Additional information can be received by comparing the data of the resistometry and pH-metry. The experimental dependence of pH on the PIL(I) solution concentration makes it possible to estimate the concentrations of Н + ions over the whole investigated range of the PIL(I) concentrations according to the following expression: (3) and hence to find the conductivity. If the assumption concerning the solution composition is true (charge carrier-hydrogen ion), then its pH can be calculated and compared with the experimental data.
As Figure 7 shows, the obtained experimental data are in complete agreement with the calculation. This (B 1 ) α 1 , K d1 = 1.2 × 10 -2 (the reaction of dissociating the traces of the acid did not completely react in the course of IL synthesis); (4) In this case, the concentrations of the components will be: The last number can be neglected since the organic ion scarcely participates in the charge motion due to its large size.
For the second stage of the dissociation of H 2 SO 4 (index 2, reaction В 2 ), the following equation can be used: Hence, we determine the value α 2 : where С 2 is the molar concentration of the ion.
Then, the dissociation degree α of the acid residual will thus determine the value of the function χ(С) in the experiments: The results of calculation according to the model are presented in Fig. 8. They show a complete agreement between the calculated and experimental data for pH(C). This confirms the correct assumption of the fact that the products of the nonorganic residual dissociation are the main charge carriers. The dependences of pH on the PIL(I) substance concentration presented in Figs. 7 and 8 were constructed using two different methods and almost entirely coincide. The simulation data show the manner in which the incomprehensible regularity presented in Fig. 7 is explained.
However, the conductivity concentration dependence calculated from (8) is in good agreement with the experiment only in diluted solutions. The PIL(I) concentration increasing it appeared two times as small as the measured conductivity. This disarrangement can imply that a parallel mechanism operates in the solution. As a result, in the case of dissociation, the PIL(I) molecule additionally forms one more ion Н + participating in reactions (4). Most likely, it could be, say, an acid residual that did not react in the process of the ionic liquid synthesis and took part in the conductivity according to the reaction В1 in system (4). The H 2 SO 4 dissociation constant (10 -2 ) is high; thus, the contribution into the conductivity of the unreacted sulphoxyl is high.
In Fig. 8b, the curve c with designation (Н + ) × 2 shows the calculated function χ(С) with account for the formation of the second ion Н + . It appeared rather close to the experimental dependence χ(С).
This suggests that, after dissociation of PIL(I) and PIL(II) that are similar in structure, the ionic solution structure can differ from the ionic structure of the anhydrous oligomer in the case of the dilution in water. It is possible that the oligomer constituent of PIL(I) R + makes its contribution into the value of ionic conduction.
Some influence on the conductivity of another mechanism may be assumed. The molecule of PIL(I) contains a group -NH-in the main chain, which can interact with water molecules forming an alkylammonium hydroxide: Hence, in the solution PIL(II) higher pH value (2.7-3.5) in comparison with the рН value of PIL(I) (1-2) is attributable to the presence of the above- Thus, the oligomer PIL(III) in the aqueous solution is low-dissociated since its dissociation should follow the law of mass action or the Ostwald dilution law following from it at С → 0: (9) where α is the dissociation degree, K d is the dissociation constant, C is the molar concentration of the PIL(III) substance. Figure 9a represents the experimental points of the function pH(C) for two separate tests (rhombs are for the first test and triangles are for the second test). Both results almost entirely coincide on the common section and express the same regularity. Solid lines show the same dependences calculated according to the values of the concentration of hydrogen ions.
This conclusion was based on the general considerations concerning the fact that the PIL(III) molecule dissociates forming one ion Н + . This conclusion can be improved analyzing the dissociation pattern of the ortho-phosphoric acid with the help of the known ref- It is used in the synthesis of PIL(III) and can be present in the composition of the oligomer dissociation products in water: The concentration of the ions Н + can hence be calculated through the dissociation degrees α 1 , α 2 , α 3 of the separate stages according to the following expression: (11) furthermore, the third summand within the brackets in (11) scarcely contributes in the total.
The calculations showed that almost complete agreement with the experiment is achieved only in the case when the value of α 1 in (11) is taken with coefficients of 0.0018 (experiment С = 0-10%) and 0.0012 (С = 10-20%). This fact can mean that no molecules of H 3 PO 4 are in the solution. Only the ions enter the solution as a result of the dissociation of the phosphate group, which is present in the oligomer products. This conclusion agrees with the known diagram of C(pH) for the products of the phosphoric acid dissociation (Fig. 10). Within the range of рН ≈ 4-5 in the solution, the anions really predominate in the solution.
For the compound PIL(IV) at any concentration, the pH values are in the neutral and weak-alkaline region (рН ≈ 7.2-7.6). In this region, the concentrations of the ions Н + and ОН-are at a level of 10 -6 -10 -7 М (Fig. 11).
The low concentrations of the ions Н + and ОНin the region of the pH neutral values cannot explain the measured rather considerable conductivity of the  scheme then their total conduction can be calculated. Under the condition of = 0 (ions Н + are absent), the calculated conductivity will be of the same order as the measured one in the diluted solution (the graph "2+3" in Fig. 11), and the value of pH does not change in this case. The diagram in Fig. 10 shows that the aqueous solution actually contains the equal fraction of the ions and within the pH range 7-8, and this fact is confirmed by the resistometry data. If the ions Н + were in the solution as the dissociation product of stage 1, the conduction should be 3-4 times higher and the pH degree should achieve values of 2-3. Thus, it is reasonable to H PO suppose that, with the participating -NH-groups, alkylammonium hydroxides are formed in water, which are the cause for the observed weak alkaline effect. The conduction is ensured by the anions-the hydrolysis product of the phosphate groupand the following dissociation of it: . It is assumed that the organic phosphates are stronger acids than H 3 PO 4 [23,24]; hence, the calculated function χ(С) "2+3" in Fig. 11 with no account for this factor should have a greater slope and be displaced in the direction of the measured data.
The temperature dependence of the conduction of the PIL(IV) ionic liquid solutions was measured with a separate portion of the solution within the temperature range of 10-66 о С. The graphs of the conduction temperature dependence on the forward and return stroke are close to linear, and they coincide within the accuracy of measurements. This corresponds to the absence of any hysteresis effects. These peculiarities can be explained by the fact that the ortho-phosphoric residuals favor the decrease in the partial pressure of steam and retard the evaporation. The temperature slope of conduction for the 21% solution is dχ/dt = 0.000439 S cm -1 °С -1 . For the 11.3% solution, the slope is dχ/dt = 0.000288 S cm -1°С-1 .
A strong nonlinearity of the function due to a high viscosity of the colloidal oligomer solution is observed for the solutions of both PIL(V) and PIL(IV) oligomers (Fig. 12).
The pH values show a rather high basic capacity; however, the concentration of the ions ОНdetermined from the experimental values of pH ensures only a third part of conductivity. It may be assumed that two free amine moiety (-NH-) in the oligomer molecule form the ions ОНsimilar to the formation of [NH 4 ] + OHat the hydrolysis of ammonia. However, this hypothesis does not simultaneously agree  HPO the ortho-phosphoric acid dissociation products contains almost solely the ions.
Interestingly, when the PIL(V) solutions are diluted, the pH value scarcely decreases, while it increases noteworthily in the PIL(IV) solutions on the contrary (Fig. 13). This fact indicates that, in the PIL(IV) with only one free amino group, which forms the hydroxide alkylammonium moieties, its dissociation with the formation of the ОНions accelerates.
The temperature dependence of the conductivity for the 20% solution is linear with a slope of dχ/dt = 0.000329 S cm -1 °С -1 .
The hysteresis is absent, the evaporation is negligible, i.e., the phosphate PILs have the best waterretaining properties in comparison with the sulphate PILs.  Fig. 11. Conductivity of (a) pH and (b) χ versus PIL(IV) concentration. Graph "2+3" is calculated according to the second and third stages of ortho-phosphoric acid (10). Empty squares are for experimental data. The PIL(VI) compound is a product of the neutralization of monoethanolamine (MEA) by the acetic acid. Monoethanolamine is the most stable amino alcohol. It is a viscous oleaginous fluid that can be unlimitedly mixed with water. The MEA formula is H 2 NC 2 H 4 OH, the density is 1.012 g/cm 3 , the melting temperature is 10.3°С, the molecular mass is М = 61.08 g mol -1 , рK = 9.5 (a weak alkaline).
According to the known regularities of organic chemistry, hydroxide ethyl amides can be formed at the interaction between the ethanol amines and carboxylic acids depending on the synthesis conditions at higher temperatures: or their salt form (at room temperature) as is shown in the scheme below: (12) Comparing the experimental data and reference table data for all the participants of the system it can be observed that the conductivity of the synthesis product is almost 20 times more than the acetic acid itself. The alkalinity of the PIL(VI) solution is determined by amine which is a part of the PIL(VI) molecule and its dissociation when diluted in water. The calculation data for the concentration dependence of the conductivity show that the measured value pH 8.5 is attained under the condition that the PIL(VI) dissociation leads to the formation of an ion ОН -. However, the concentration of the ОНions in the solution appears negligible (≈7 × 10 -9 М) in this case; hence, they could not make a noteworthy contribution to the conductivity.
Thus, the known properties of both MEA and acetic acid do not explain the conductivity mechanism for the aqueous solution of their interaction product. Apparently, the mechanism of the PIL(VI) formation differs from the hypothesis presented by equation (12).
The temperature function χ(Т) of the conductivity of the PIL(VI) solutions has an almost linear form; hence, it was recorded within a range of low temperatures where the evaporation effects are not noticeable. The temperature slope is dχ/dt = 0.000892 S cm -1 °С -1 .

COMPARATIVE ANALYSIS OF IONIC LIQUIDS
The information on the general properties of the system of the studied ionic liquids can be received comparing their physical and chemical characteristics. They differ in the values of pH in the range from 1 to 10, ion-generating inorganic acids, and molar masses. The concentration dependences of conductivity as an important characteristic feature of the ionic liquids are shown in Fig. 14.
The conduction of the ionic liquid solutions is sufficiently high (almost such as in the aqueous solutions of inorganic salts) and greatly changes in the series of the studied PILs. It is the highest in the sulphate PILs-PIL(I), PIL(II), and it is the lowest in the phosphate PILs-PIL(III), PIL(IV), and PIL(V). For all the PILs, the function χ(С) has a common feature: a strong nonlinearity. The second important characteristic of the PIL aqueous solutions is the value of pH. The concentration dependences of pH of the studied ionic liquids are shown in Fig. 15. As the graphs show when the aqueous solutions were diluted or concentrated, the values of pH of all the types of ionic liquids change within rather narrow limits of approximately one unit. This means that the conduction mechanism at a considerable dilution (10, 20% → 0) of the aqueous solutions of ionic liquids does not change, though it is varied for different types of liquids.
It we compare all the studied ionic liquids, we can state that there exists an evident correlation between their values of pH (Fig. 15) and conductivity in the aqueous solutions (Fig. 14). The correlation shown in Fig. 16 has an interesting regularity-the conductivity depends on pH only within the range рН = 0-4, while the conduction scarcely depends on pH at рН = 4-10. The conduction of the sulphate PIL(I), PIL(II) is ensured by the free ions Н + from the anions . The ОНgroups of alkyl ammonium moieties formed at the interaction of the free groups -NH-with water make a contribution to the ionic conduction in PIL(II). This leads to a decrease in the solution conduction. Another three compounds, PIL(III), PIL(IV), and PIL(V), are phosphate esters. In them the dissociation products of the phosphate groups form and slow-moving anions. Thus, the conductivity of all the phosphate esters is almost the same and much lower than that of PIL(I) and PIL(II).
Additional explanations can be obtained comparing the temperature slopes of the conductivity dχ/dt for different ionic liquids (Fig. 17). The temperature function χ(t) is associated with the activation energy Е А of the charge carriers in liquid conductors by the Arrhenius equation as follows: (13) where χ 0 is the constant, Т = (t + 273) is the temperature in the absolute scale, and R = 8.314 J/(mol deg) is the gas constant.
According to the theory of the absolute rates of the Eyring reactions, the activation energy Е А means the lowest energy necessary for the transition of the ion from one stable state to another through the energy barrier. The calculation data for the activation energy of the charge carriers in the solutions of the separate ionic liquids obtained from equation (13) show that the value of dχ/dt for the ions Н + in the aqueous solutions is one to two orders of magnitude less than in the solutions of all the ionic liquids (point Н + on Fig. 17a). However, the conduction activation energy in all cases  (Fig. 17b).
It is well known that the ions Н + and ОНin the aqueous solutions move according to the anomalous mechanism by proton jumps between the contacting hydroxonium ion-water molecule pairs (token mechanism). Thus, the formal motion of the ОНions in the alkalites is actually the motion of protons in the opposite direction, i.e., the moving charge carrier is the same, a proton. However, the typical transfer constant (the limiting equivalent conduction of the ion ОНat С → 0 λ 0 = 171) is twice as little than that of the ion Н + (λ 0 = 350). Thus, the pH growing there also nearly doubles the conduction activation energy of the aqueous solutions of the ionic liquids where the charge carriers are the ions Н + (Fig. 17b). In the solutions of the phosphate oligoesters PIL(III), PIL(IV), and PIL(V), the carriers of the moving charges are the slow-moving anions; hence, the conduction activation energy Е А is higher.
Note that, on the correlation graph in Fig. 17b, the scatter of the points is rather considerable. This fact is partially a result of the experimental errors due to the different conditions of the tests (temperature 10-23°С, a small number of samples and the loss at the operations with little solution volumes of 10-20 mL, etc.). Meanwhile, the correlation is not a functional dependence. The separate ionic liquids considerably differ in structure and have distinct individual peculiarities. For example, the charge motion kinetics is influenced by various reasons-the viscosity of the solutions, the molecular masses of oligoesters-on which depend the molar concentration values and many other factors of the structure of a specific compound. However, in spite of the scatter of the points, particularly noticeable due to a small number of them, the regularities formulated on the basis of the correlations shown in Fig. 12 are evident and proved in a logical way.

CONCLUSIONS
(1) A low-frequency sensor microprocessor resistometer was designed and manufactured, a software code was formed, and flowing sensors to measure the resistance of the aqueous solution volumes up to 50 mm 3 and to determine their conductivity were developed and produced.
(2) The methods of computer resistometry and pH-metry were used to perform an integrated study of the properties of the aqueous solutions of six samples of the ionic liquids synthesized on the basis of the interaction products of the organic and inorganic acids with the organic acyclic oligomers. The dependences of the conductivity and pH on the concentrations of the group of ionic liquids, the temperature slopes of the conductivity dχ/dT, the conduction activation energy, and the parameters of the dissociation processes (dissociation constants, the dissociation degree) were established. The relative contribution of the main possible charge carriers to the conduction of the aqueous solution was estimated from the obtained data on the basis of the known theories of conduction and electrolytic dissociation. This fact allowed some conclusions on the correlation between the physical and chemical properties of the aqueous solutions of the ionic liquids and the supposed structure of them.