Subscriber access provided by CORNELL UNIVERSITY LIBRARY
Article
Dipolar Self-Assembling in Mixtures of Propylene Carbonate and Dimethyl Sulfoxide as Reveals in the Orientational Entropy Iwona Plowas, Jolanta Swiergiel, and Jan Jadzyn J. Phys. Chem. B, Just Accepted Manuscript • DOI: 10.1021/acs.jpcb.6b04588 • Publication Date (Web): 26 Jul 2016 Downloaded from http://pubs.acs.org on July 29, 2016
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
The Journal of Physical Chemistry B is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 29
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
Dipolar Self-Assembling in Mixtures of Propylene Carbonate and Dimethyl Sulfoxide as Reveals in the Orientational Entropy Iwona Płowaś*, Jolanta Świergiel and Jan Jadżyn Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland E-mail: [email protected] Phone.: +48 61 86 95 162
ACS Paragon Plus Environment
The Journal of Physical Chemistry
2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
ABSTRACT The paper presents results of the static dielectric studies performed for mixtures of two strongly polar liquids important from technological point of view: propylene carbonate (PC) and dimethyl sulfoxide (DMSO). The dielectric data were analyzed in terms of the molar orientational entropy increment induced by the probing electric field. It was found that the two polar liquids in the neat state reveal quite different molecular organization in terms of the dipole-dipole self-assembling: propylene carbonate exhibits a dipolar coupling of the head-totail type while in dimethyl sulfoxide one observes an extreme restriction of dipolar association in any form. In PC + DMSO mixtures, the disintegration of the dipolar ensembles of PC molecules takes place and the progress of that process is strictly proportional to the concentration of DMSO. The static permittivity of mixtures of such differently self-organized liquids exhibits a positive deviation from the additive rule and the deviation develops symmetrically within the concentration scale.
ACS Paragon Plus Environment
Page 2 of 29
Page 3 of 29
The Journal of Physical Chemistry
3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
INTRODUCTION Although the designing of liquid mixtures exhibiting the physicochemical properties assumed in advance is a real challenge for chemical engineering, this type of task is frequently undertaken by the chemical engineers. This is due to the natural needs of processes which are “fast, efficient and low-energy”. Besides, the most favorable would be the processes which are friendly for the environment, i.e. the chemicals used should be classified as “a green chemistry”. As the properties of any mixture of liquids are stored in the intermolecular interactions between the components, an importance and usefulness of the basic research are here obvious. Propylene carbonate (PC) and dimethyl sulfoxide (DMSO), the chemical structure of which is presented on Figure 1, are important representatives of reagents that satisfy the requirements of "green chemistry" and whose usefulness in many industries has been fully confirmed.1-5
Figure 1. The chemical structure of propylene carbonate (PC) and dimethyl sulfoxide (DMSO). Undoubtedly, more universal liquid is DMSO, the application of which extends from the electrochemistry to medicine.6-8 Particularly spectacular and extremely anomalous properties exhibit the mixtures of DMSO (m.p. = 18°C) and water for which a surprisingly low freezing point at about -40°C is measured for the molar fraction of DMSO of about 0.35 in the mixture.9,10 Propylene carbonate (m.p. = -49°C, b.p. = 242°C), in turn, is very suitable
ACS Paragon Plus Environment
The Journal of Physical Chemistry
4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
as an electrolyte solvent in lithium ion batteries11,12 or as a plasticizer for solid polymer electrolytes.13 Both solvents, PC and DMSO, are highly polar liquids what is connected mainly with high values of their molecular dipole moments (4.94 D14 for PC and 3.96 D15 for DMSO). However, the difference of about 1 D in the dipole moments seems to be not sufficient to explain a fairly large difference in the static permittivities ( ε S ) of these liquids ( ε S = 64.4 for PC and 46.7 for DMSO, at 25°C), the more that the ratio of their molar volumes (84.7 cm3/mol for PC and 71 cm3/mol for DMSO, at 25°C) works rather towards leveling the difference in the permittivities of the both liquids. Of course, an explanation of the permittivity difference can be made by the recognition of the type of self-assembling occurring between the molecular dipoles of PC and DMSO. Hence, one is able to identify the possible intermolecular entities which are formed in these liquids and influence the final value of their static permittivities. Unfortunately, the published experimental papers on this subject show large discrepancies in the assessment of the type of dipolar aggregation occurring in PC and DMSO. This assessment in the majority of the papers is based on the Kirkwood correlation factor ( g K ), the value of which is, however, quite difficult for credible determination. It stems from the fact that the factor g K depends mainly on the difference between the static ( ε S ) and high-frequency ( ε ∞ ) permittivities of studied liquid and there are serious experimental problems with precise determination of ε ∞ . The wider analysis of that important topic in molecular physics was presented in recent paper,16 and here we only briefly show the current state of research on the dipolar aggregation in liquid PC and DMSO. The experimental data published in the literature are particularly divergent in the case of PC: for available extreme experimental values of ε ∞ = 2.22 or 4.14,17 one obtains quite different image of dipolar association in that liquid. Basing on the above values of ε ∞ , the
ACS Paragon Plus Environment
Page 4 of 29
Page 5 of 29
The Journal of Physical Chemistry
5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
calculated Kirkwood correlation factor g K equals either to 1.23 (what points out for not too high but clear linear association of the head-to-tail type) or to 0.57 (strongly antiparallel association). A slightly smaller, but also confusing discrepancy concerns the dipolar association in DMSO,17 for which the extreme values of g K which can be found, are 0.52 or 1.04, however here, most published data are not far from g K = 1 .18-22 In this paper we analyze the data of the static permittivity of PC and DMSO, as well as their mixtures, in the whole range of concentrations and at different temperatures. The PC + DMSO mixtures are used in numerous physico-chemical processes, in particular as media for electrolytes for lithium batteries. So, knowledge of the dielectric properties of the tested liquids and the relationship of these characteristics with the type of occurring intermolecular interactions, is the basis for the design of liquid mixtures with suitable properties. It is obvious that such investigation requires a reliable method of analysis the static dielectric data in terms of the structure of the intermolecular entities which can be formed in studied liquid. As shown above, the Kirkwood correlation factor, due to high uncertainty in the choice of ε ∞ , cannot constitute a solid basis for the structural discussions. In this work the basis for such discussion is temperature derivative of the static permittivity,23 which reflects the actual orientational abilities of molecular dipoles in studied liquid. These abilities correspond directly to kind of the dipolar intermolecular entities existing in studied liquid.
EXPERIMENTAL SECTION Propylene carbonate (4-methyl-1,3-dioxolane-2-one), C4H6O3, and dimethyl sulfoxide, (CH3)2S=O, from Sigma-Aldrich, the both of purity 99.9%, were stored over molecular sieves (4 Å) for several weeks. At the time, they were placed in desiccator over silica gel. The measurements were performed for PC + DMSO mixtures in the whole concentration range.
ACS Paragon Plus Environment
The Journal of Physical Chemistry
6 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The solutions were prepared by weighting with an accuracy of ± 1·10-4 g. The standard uncertainty for the mole fraction determination was 2·10-4. The complex permittivity spectra were recorded with the use of an HP 4194A impedance/gain phase analyzer in the frequency range from 100 Hz to 5 MHz. The measurements were performed in the temperature range from 253.15 K to 353.15 K. At first, the samples were cooled down (approximately with 2 K/min) to 253 K and next the measurements were performed for increasing temperature. The temperature of the measuring cell was controlled with a “Scientific Instruments” device, model 9700, within ± 2·10-3 K. The details on the used experimental set-up can be found in recent paper.24 The standard uncertainty for the permittivity determination was 0.05.
RESULT AND DISCUSSION Figure 2 presents the real (a) and imaginary (b) parts of the dielectric spectra recorded at different temperatures for the mixture of PC + DMSO with the mole fraction xDMSO ≈ 0.9 , as an example. An apparent increase of the static permittivity, which is observed in the low frequency region of the real spectra (a), reflects the polarization effects on the electrodes of measuring cell due to ionic impurities present in liquids. The conduction of those residual ions causes the energy losses represented by the imaginary part (b) of the spectra. As can be seen in Figure 2, in our experiment one records the phase transition between the solid and liquid phases. In the used temperature range, that transition is observed for PC + DMSO mixtures with the mole fractions from the range: 0.6 ≤ xDMSO ≤1.0 , i.e. for the mixtures rich in DMSO.
ACS Paragon Plus Environment
Page 6 of 29
Page 7 of 29
The Journal of Physical Chemistry
7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 2. The real (a) and imaginary (b) parts of the dielectric spectra of PC + DMSO mixture with the mole fraction of xDMSO ≈ 0.9 , recorded in the solid and liquid phases of the mixture upon heating. Figure 3 presents the static permittivity of the mixtures of PC + DMSO as a function of their composition and temperature, obtained from analysis of the real part of the dielectric spectra (a). A sharp drop in the permittivity which occurs in several mixtures is due to the liquid-to-solid transition. The temperatures of the transitions allowed one to draw up a part of the phase diagram for the mixtures of PC + DMSO which, as depicted in Figure 4, is in a good consistency with m.p. of neat PC.25
Figure 3. Concentration and temperature dependences of the static permittivity of propylene carbonate + dimethyl sulfoxide solutions.
ACS Paragon Plus Environment
The Journal of Physical Chemistry
Page 8 of 29
8 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 4. The phase diagram for the mixtures of PC + DMSO. As mentioned above, the analysis of the measured static permittivity, ε S , and the evaluation of usefulness of that quantity in determination of the structure of dipolar liquids, will be based on temperature derivative of the permittivity, d ε S dT . In 1958, Fröhlich23 showed as the first, that this derivative is proportional to the change in entropy of dipolar liquid due to an orienting effect caused by the probing electric field of intensity E: ∆S (T ) E
2
≡
S (T , E ) − S0 (T ) E
2
=
ε 0 dε S 2 dT
(T ) ,
(1)
where S0 (T ) denotes the entropy in absence of the electric field, T is the absolute temperature and ε0 = 8.85 pF/m is the permittivity of free space. Since in the most cases an applying of electric field causes an ordering of molecular dipoles in liquid, the entropy increment ∆S is usually negative. Some exceptions may be encountered in the pre-transitional region of certain nematogenic liquids.26-28 Then, the prenematic antiparallel arrangement of dipoles can be partially destroyed by external electric field what leads to an increase of molecular disorder in these liquids, i.e. ∆S can change its sign to the positive. An important note on possible evolution of the increment ∆S with the temperature change, results directly from thermodynamically obvious principle, namely, that any type of the dipole-dipole assembling occurring in a given liquid enhances itself, when the temperature decreases. That is, in the case of linear dipolar association of the head-to tail type, the absolute
ACS Paragon Plus Environment
Page 9 of 29
The Journal of Physical Chemistry
9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
value of ∆S will increase with decreasing temperatures while the antiparallel association will lead to an opposite effect, namely, to decrease of ∆S . And only in very exceptional, mentioned above cases of liquid crystalline materials, the increment can attain zero or even can be a positive. Between these significantly different types of dipolar aggregation there is a natural place for dipolar liquids, in which, for various reasons, mostly for the steric ones, the aggregation is severely limited. Then, in principle, there are no reasons for ∆S to be temperature dependent.
Figure 5. Increment of the orientational entropy determined from eq 1 for the mixtures of propylene carbonate (PC) and dimethyl sulfoxide (DMSO) of different compositions of the mixtures and at different temperatures. Figure 5 presents temperature dependences of the entropy increment determined for solutions with different mole fractions of DMSO in PC. Immediately striking is significantly different behavior of the increment in the neat liquids. In the case of PC, we have undoubtedly faced with a phenomenon of the head-to-tail association of dipoles, while DMSO demonstrates, anyway as expected, the virtual absence of aggregation of the molecular dipoles.18-21 Comparison of these conclusions with those resulting from the theoretical calculations is somewhat difficult because the calculations mostly involve interactions between the isolated molecules.29 Then, an optimization of the structure of DMSO and PC dimers leads
ACS Paragon Plus Environment
The Journal of Physical Chemistry
10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
often to an antiparallel mutual orientation of the two molecules of the compounds.30,31 An explanation for that apparent contradiction with our experimental results can be found in the paper by Silva et al.32 The authors have used the Monte Carlo simulations to determine the structure and other thermodynamic properties of PC. As the main result of the paper is a finding that in the neat liquid state the electrostatic interactions lead the neighboring PC molecules to a preferential head-to-tail alignment. Next, an important result of the simulation refers to the situation in the gas phase. Here, the most energetically favorable is the antiparallel orientation of the dipolar molecules of the PC. So, our experimental results very well confirm the simulation results obtained by Silva et al. for neat liquid PC. However, there is some problem concerning the results shown in Figure 5. Namely, the increments ∆S were obtained by differentiation of the permittivity which was measured in the cell, the volume of which is virtually temperature independent. It means that with the change of temperature, changes itself also the number of dipoles in the measuring cell what can cause the apparent modifications in the orientational effects. Removing of those doubts is basically simple, just multiply the increment from Figure 5 by the molar volume ( VM ) of studied liquid at a given temperature: ∆S (T ) VM (T ) E 2 . After that, under consideration is the orientational effects related to one mole, this is the Avogadro number of dipoles. Figure 6 presents the increment of the orientational entropy per one mole of dipolar molecules of chosen solutions of PC + DMSO, as a function of temperature. In the molar approach, the increment of entropy obviously changed its value in comparison to that at constant volume, but now it reflects exclusively the current resultant dipole moment of the mole of molecules of studied liquid. As seen in Figure 6, the molar entropy increment in neat DMSO is decidedly independent of the temperature, thereby maintaining the previous conclusion on the virtual lack of dipolar aggregation in that liquid. As previously, the different behavior of PC in comparison to DMSO, is clearly seen in the figure. Certainly, here
ACS Paragon Plus Environment
Page 10 of 29
Page 11 of 29
The Journal of Physical Chemistry
11 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
we are dealing with the "head-to-tail" dipolar aggregation as the prevailing type of interaction in liquid PC.
Figure 6. Temperature dependence of the increment of the molar orientational entropy for several solutions of PC + DMSO. The molar volume of the mixtures were obtained from the data for neat components,33-35 assuming the additivity rule. If the slopes of temperature dependence of the molar entropy increment, presented in Figure 6, can be taken as some measure of an extension of the parallel association of molecular dipoles, then now we can display an evolution of that extension with increasing concentrations of DMSO in PC. Figure 7 shows dependence of the slopes (denoted as m) of the straight lines from Figure 6 (and others not shown on the figure), as a function of the mole fraction of DMSO in the mixtures with PC. As can be seen, the degree of the linear selfassociation of PC molecules decreases in a roughly linear way, as far as the mole fraction of DMSO increases. As a matter of fact, m represents the second derivative of the permittivity dependence on the temperature. The difference in temperature behavior of the entropy increment of neat DMSO and PC, clearly seen in Fig. 6, undoubtedly differentiates these two compounds from point of view the self-association ability of their molecules. However, used in this study the research method, despite its undoubtedly high sensitivity and uniqueness, does not provide quantitative assessment of the dipolar assembles. In particular, we do not know how extended is the self-
ACS Paragon Plus Environment
The Journal of Physical Chemistry
12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
association of PC molecules, and how many molecules, on average, take part in that process. Obtaining such quantitative information requires the use of real structural pattern as a reference. Fig. 8 presents a comparison of temperature dependences of the molar entropy increments of studied DMSO and PC as well as the dependences for two compounds which can be taken here as kind of references: a liquid secondary amide, N-methylacetamide (NMA), which strongly self-associates in chains, and n-pentylcyanobiphenyl (5CB), which belong to the most antiparallel dimerized liquid.
Figure 7. The slops (m) of temperature dependence of the increment of molar orientational entropy as a function of the mole fraction of DMSO dissolved in PC.
Figure 8. Temperature dependences of the increments of molar orientational entropy of neat DMSO and PC. For comparison are presented dependences for two significantly selfassembled compounds: N-methylacetamide (NMA),36 the molecules of which form strongly elongated hydrogen-bonded chains (head-to-tail) and n-pentylcyanobiphenyl (5CB),16 dipolar liquid where the antiparallel dimers are strongly dominating intermolecular entities. Molar volumes of NMA were obtained from the data.37
ACS Paragon Plus Environment
Page 12 of 29
Page 13 of 29
The Journal of Physical Chemistry
13 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Notwithstanding the significant difference in the energy of the dipolar interactions and the hydrogen bonds, Figure 8 shows that the dipolar self-association in liquid PC is of the heat-to tail type. At the end of the work, seems to be interesting to see, how the static permittivity behaves from the point of view of its additivity, in the liquid mixtures of such fairly well defined intermolecular interactions. The result can be interesting for both designers of liquid mixtures, who usually apply the rule of additivity of permittivity, as well as for researchers who are looking for the relationship between the dipolar interactions and the non-additive behavior of the permittivity in liquid mixtures.38,39
Figure 9. The concentration dependences of (a) the static permittivity and (b) its deviation from the additivity (eq 2) in the mixtures of PC + DMSO, at three chosen (from Figure 3) temperatures. The dashed lines in (a) represent a supposed additive behavior of the permittivity in the mixtures. Figure 9a presents dependence of the static permittivity of PC + DMSO mixtures on the mole fraction of DMSO, at chosen (from Figure 3) three temperatures. Part b of the figure presents the permittivity deviation from additivity ( ∆ε S ):
∆ε S = ε S − (1 − xDMSO ) ε SPC + xDMSOε SDMSO ,
ACS Paragon Plus Environment
(2)
The Journal of Physical Chemistry
14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
where ε S denotes the static permittivity measured at the given temperature for solution where the mole fraction of DMSO is equal xDMSO , while ε SPC and ε SDMSO are the permittivities of neat components of the mixture, measured at the same temperature. As is apparent from Figure 9b, the static permittivity measured for the mixtures of PC + DMSO shows a positive deviation from the additivity rule and the maximum of deviation corresponds roughly to the PC : DMSO molecules ratio of 1:1, and the value of the deviation at the maximum attains about 5% of the permittivity value, depending somewhat on the temperature.
CONCLUSIONS The following conclusions, resulting from the presented above experimental data, seem to be important. First of all, it was shown that the increment of the molar orientational entropy and its temperature behavior allow one for much unambiguous determination of the molecular structure of dipolar liquids than the Kirkwood correlation factor with its problems in reliable determination of the high-frequency permittivity ε∞. On the basis of the experimental dielectric data obtained for two liquids of high technical and scientific impact, namely, propylene carbonate and dimethyl sulfoxide, it was found that the molecular dipoles in the first liquid exhibit a tendency to the self-assembling in the parallel, head-to-tail way, while in the other liquid the dipolar self-assembling is extremely restricted. Experimental identification the way of the molecular aggregation in PC, which strongly support the result of the Monte Carlo simulations,32 allows one to understanding of the significantly increased permittivity of that liquid in comparison with that of DMSO. The studies showed that in PC + DMSO solutions the self-assembles composed of PC molecules gradually disintegrate as the concentration of DMSO is increasing. And finally, it was found that in the mixtures of differently self-organized liquids, the static permittivity exhibits a positive deviation from the additivity rule and, in the
ACS Paragon Plus Environment
Page 14 of 29
Page 15 of 29
The Journal of Physical Chemistry
15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
concentration scale, that deviation (defined by eq 2) is more or less symmetrical. The deviation, in its maximum, reaches approximately 5% of the value of the measured static permittivity (at 303 K).
ACS Paragon Plus Environment
The Journal of Physical Chemistry
Page 16 of 29
16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
REFERENCES (1)
Parker, H. L.; Sherwood, J.; Hunt, A. J.; Clark, J. H. Cyclic Carbonates as Green
Alternative Solvents for the Heck Reaction. ACS Sustainable Chem. Eng. 2014, 2, 1739−1742. (2) Verevkin, S. P.; Emel'yanenko, V. N.; Bayardon, J.; Schäffner, B.; Baumann, W.; Börner, A. Asymmetric Hydrogenation of Nonfunctionalized Olefins in Propylene Carbonate−Kinetic or Thermodynamic Control? Ind. Eng. Chem. Res. 2012, 51, 126−132. (3) Xu, D.; Wang, Z. L.; Xu, J. J.; Zhang, L. L.; Zhang, X. B. Novel DMSO-Based Electrolyte for High Performance Rechargeable Li−O2 Batteries. Chem. Commun. 2012, 48, 6948−6950. (4) Kötz, R.; Carlen, M. Principles and Applications of Electrochemical Capacitors.
Electrochim. Acta 2000, 45, 2483−2498. (5) Conway, B. E. Electrochemical Supercapacitors; Kluwer Academic/Plenum Publishers: New York, 1999. (6) Jacob, S. W.; De La Torre, J. C. Dimethyl Sulfoxide (DMSO) in Trauma and Disease; CRC Press: Boca Raton, 2015. (7) Capriotti, K.; Capriotti, J. A. Dimethyl Sulfoxide: History, Chemistry, and Clinical Utility in Dermatology. J. Clin. Aesthet. Dermatol. 2012, 5, 24–26. (8) Yu, Z.-W.; Quinn, P. J. Dimethyl sulfoxide: A Review of its Applications in Cell Biology. Biosci. Rep. 1994, 14, 259−281. (9) Rasmussen,
D.
H.;
Mackenzie,
A.
P.
Phase
Diagram
for
the
System
Water−Dimethylsulphoxide. Nature 1968, 220, 1315−1317. (10) Płowaś, I.; Świergiel, J.; Jadżyn, J. Relative Static Permittivity of Dimethyl Sulfoxide + Water Mixtures. J. Chem. Eng. Data 2013, 58, 1741−1746. (11) Bhatt, M. D.; O’Dwyera, C. Solid Electrolyte Interphases at Li-Ion Battery Graphitic Anodes Inpropylene Carbonate (PC)-Based Electrolytes Containing FEC, LiBOB, and LiDFOB as Additives. Chem. Phys. Lett. 2015, 618, 208–213. (12) Richardson, P. M.; Voice, A. M.; Ward, I. M. Pulsed-Field Gradient NMR Self Diffusion and Ionic Conductivity Measurements for Liquid Electrolytes Containing LiBF4 and Propylene Carbonate. Electrochim. Acta 2014, 130, 606–618. (13) Das, S.; Ghosh, A. Ionic Conductivity and Dielectric Permittivity of PEO−LiClO4 Solid Polymer Electrolyte Plasticized with Propylene Carbonate. AIP Advances 2015, 5, 027125.
ACS Paragon Plus Environment
Page 17 of 29
The Journal of Physical Chemistry
17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
(14) Kempa, R.; Lee, W. H. The Dipole Moments of Some Cyclic Carbonates. J. Chem.
Soc. 1958, 1936−1938. (15) Driezler, H.; Dendl, G. Rotationsspektrum, r0-Struktur und Dipolmoment von Dimethylsulfoxyd. Naturforsch. A 1964, 19, 512−514. (16) Świergiel, J.; Płowaś, I.; Jadżyn, J. On Investigation of Aggregation of Molecular Dipoles in Liquids. J. Mol. Liq. 2016, 220, 879−882. (17) Barthel, J.; Bachhuber, K.; Buchner, R.; Gill, J. B.; Kleebauer, M. Dielectric Spectra of Some Common Solvents in the Microwave Region. Dipolar Aprotic Solvents and Amides.
Chem. Phys. Lett. 1990, 167, 62−66. (18) Prestbo, E. W.; McHale, J. L. Static Dielectric Constants and Kirkwood Correlation Factors of Dimethyl Sulfoxide/Carbon Tetrachloride Solutions. J. Chem. Eng. Data 1984, 29, 387−389. (19) Kaatze, U.; Pottel, R.; Schaefer, M. Dielectric Spectrum of Dimethyl Sulfoxide/Water Mixtures as a Function of Composition. J. Phys. Chem. 1989, 93, 5623−5627. (20) Vechi, S. M.; Skaf, M. S. Collision-Induced Effects on the Dielectric Properties of Liquid Dimethylsulfoxide. J. Braz. Chem. Soc. 2002, 13, 583−591. (21) Sengwa, R. J.; Sankhla, S.; Khatri, V. Dielectric Characterization and Molecular Interaction Behaviour in Binary Mixtures of Amides with Dimethylsulphoxide and 1,4Dioxane. J. Mol. Liq. 2010, 151, 17−22. (22) Ritzoulis, G. Excess Properties of the Binary Liquid Systems Dimethylsulfoxide + Isopropanol and Propylene Carbonate + Isopropanol. Can. J. Chem. 1989, 67, 1105−1108. (23) Fröhlich, H. Theory of Dielectrics, 2nd ed.; Clarendon Press: Oxford, 1958. (24) Świergiel, J.; Jadżyn, J. Static Dielectric Permittivity of Homologous Series of Liquid Cyclic Ethers 3n-crown-n, n = 4 to 6. J. Chem. Eng. Data 2012, 57, 2271−2274. (25) Ding, M. S.; Xu, K.; Jow, T. R. Liquid-Solid Phase Diagrams of Binary Carbonates for Lithium Batteries. J. Electrochem. Soc. 2000, 147, 1688−1694. (26) Jadżyn, J.; Czechowski, G. Prenematic Behavior of the Electric-Field-Induced Increment of the Basic Thermodynamic Quantities of Isotropic Mesogenic Liquids of Different Polarity. J. Phys. Chem. B 2007, 111, 3727−3729. (27) Jadżyn, J.; Czechowski, G.; Déjardin, J.-L. Dynamics of the Self-Assembling of Mesogenic Molecules in the Prenematic Region of Isotropic Liquid. J. Phys. Chem. B 2008,
112, 4948−4952.
ACS Paragon Plus Environment
The Journal of Physical Chemistry
18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
(28) Jadżyn, J.; Sokołowska, U.; Déjardin, J.-L. Temperature Behavior of the Electric Field-Induced Entropy Increment within a Homologous Series of Nematogenic Compounds.
J. Phys. Chem. B 2008, 112, 9050–9052. (29) Jensen, J. H.; Gordon, M. S. An Approximate Formula for the Intermolecular Pauli Repulsion Between Closed Shell Molecules. II. Application to the Effective Fragment Potential Method. J. Chem. Phys. 1998, 108, 4772−4782. (30) Varnali, T. Associated Species of Dimethylsulfoxide: Semiempirical Modeling. Struct.
Chem. 1996, 7, 111−118. (31) Kollipost, F.; Hesse, S.; Lee, J. J.; Suhm, M. A. Dimers of Cyclic Carbonates: Chirality Recognition in Battery Solvents and Energy Storage. Phys. Chem. Chem. Phys.
2011, 13, 14176−14182. (32) Silva, L. B.; Gomide Freitas, L. C. Structural and Thermodynamic Properties of Liquid Ethylene Carbonate and Propylene Carbonate by Monte Carlo Simulations. J. Mol.
Struct.: THEOCHEM 2007, 806, 23−34. (33) Moumouzias, G.; Ritzoulis, G. Viscosities and Densities for Propylene Carbonate + Toluene at 15, 20, 25, 30, and 35°C. J. Chem. Eng. Data 1992, 37, 482−483. (34) Barthel, J.; Neueder, R.; Roch, H. Density, Relative Permittivity, and Viscosity of Propylene Carbonate + Dimethoxyethane Mixtures from 25°C to 125°C. J. Chem. Eng. Data
2000, 45, 1007−1011. (35) Grande, M. C.; Garcia, M.; Marschoff, C. M. Density and Viscosity of Anhydrous Mixtures of Dimethylsulfoxide with Acetonitrile in the Range (298.15 to 318.15) K. J. Chem.
Eng. Data 2009, 54, 652−658. (36) Świergiel, J.; Jadżyn, J. Fractional Stokes-Einstein-Debye Relation and Orientational Entropy Effects in Strongly Hydrogen-Bonded Liquid Amides. Phys. Chem. Chem. Phys.
2011, 13, 3911−3916. (37) Nallani, S.; Boodida, S.; Tangeda, S. J. Density and Speed of Sound of Binary Mixtures of N-Methylacetamide with Ethyl Acetate, Ethyl Chloroacetate, and Ethyl Cyanoacetate in the Temperature Interval (303.15 to 318.15) K. J. Chem. Eng. Data 2007, 52, 405−409. (38) Iglesias, T. P. On the Definition of the Excess Permittivity of a Fluid Mixture.
J. Chem. Thermodyn. 2008, 40, 1038−1039. (39) Iglesias, T. P.; Reis, J. C. R. Separating the Contributions of the Volume Change upon Mixing, Permittivity Contrast and Molecular Interactions in the Excess Relative Permittivity of Liquid Mixtures. Phys. Chem. Chem. Phys. 2015, 17, 13315−13322.
ACS Paragon Plus Environment
Page 18 of 29
Page 19 of 29
The Journal of Physical Chemistry
19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
TOC GRAPHICS
ACS Paragon Plus Environment
The Journal of Physical Chemistry
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 1. The chemical structure of propylene carbonate (PC) and dimethyl sulfoxide (DMSO). 80x43mm (300 x 300 DPI)
ACS Paragon Plus Environment
Page 20 of 29
Page 21 of 29
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
Figure 2. The real (a) and imaginary (b) parts of the dielectric spectra of PC + DMSO mixture with the mole fraction of xDMSO ≈ 0.9, recorded in the solid and liquid phases of the mixture upon heating. 138x254mm (300 x 300 DPI)
ACS Paragon Plus Environment
The Journal of Physical Chemistry
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 3. Concentration and temperature dependences of the static permittivity of propylene carbonate + dimethyl sulfoxide solutions. 119x109mm (300 x 300 DPI)
ACS Paragon Plus Environment
Page 22 of 29
Page 23 of 29
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
Figure 4. The phase diagram for the mixtures of PC + DMSO. 100x66mm (300 x 300 DPI)
ACS Paragon Plus Environment
The Journal of Physical Chemistry
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 5. Increment of the orientational entropy determined from eq 1 for the mixtures of propylene carbonate (PC) and dimethyl sulfoxide (DMSO) of different compositions of the mixtures and at different temperatures. 127x110mm (300 x 300 DPI)
ACS Paragon Plus Environment
Page 24 of 29
Page 25 of 29
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
Figure 6. Temperature dependence of the increment of the molar orientational entropy for several solutions of PC + DMSO. The molar volume of the mixtures were obtained from the data for neat components,33-35 assuming the additivity rule. 115x80mm (300 x 300 DPI)
ACS Paragon Plus Environment
The Journal of Physical Chemistry
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 7. The slops (m) of temperature dependence of the increment of molar orientational entropy as a function of the mole fraction of DMSO dissolved in PC. 124x97mm (300 x 300 DPI)
ACS Paragon Plus Environment
Page 26 of 29
Page 27 of 29
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
Figure 8. Temperature dependences of the increments of molar orientational entropy of neat DMSO and PC. For comparison are presented dependences for two significantly self-assembled compounds: Nmethylacetamide (NMA),36 the molecules of which form strongly elongated hydrogen-bonded chains (headto-tail) and n-pentylcyanobiphenyl (5CB),16 dipolar liquid where the antiparallel dimers are strongly dominating intermolecular entities. Molar volumes of NMA were obtained from the data.37 122x87mm (300 x 300 DPI)
ACS Paragon Plus Environment
The Journal of Physical Chemistry
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 9. The concentration dependences of (a) the static permittivity and (b) its deviation from the additivity (eq 2) in the mixtures of PC + DMSO, at three chosen (from Figure 3) temperatures. The dashed lines in (a) represent a supposed additive behavior of the permittivity in the mixtures. 161x167mm (300 x 300 DPI)
ACS Paragon Plus Environment
Page 28 of 29
Page 29 of 29
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
TOC 50x37mm (300 x 300 DPI)
ACS Paragon Plus Environment
Article
Dipolar Self-Assembling in Mixtures of Propylene Carbonate and Dimethyl Sulfoxide as Reveals in the Orientational Entropy Iwona Plowas, Jolanta Swiergiel, and Jan Jadzyn J. Phys. Chem. B, Just Accepted Manuscript • DOI: 10.1021/acs.jpcb.6b04588 • Publication Date (Web): 26 Jul 2016 Downloaded from http://pubs.acs.org on July 29, 2016
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
The Journal of Physical Chemistry B is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 29
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
Dipolar Self-Assembling in Mixtures of Propylene Carbonate and Dimethyl Sulfoxide as Reveals in the Orientational Entropy Iwona Płowaś*, Jolanta Świergiel and Jan Jadżyn Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland E-mail: [email protected] Phone.: +48 61 86 95 162
ACS Paragon Plus Environment
The Journal of Physical Chemistry
2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
ABSTRACT The paper presents results of the static dielectric studies performed for mixtures of two strongly polar liquids important from technological point of view: propylene carbonate (PC) and dimethyl sulfoxide (DMSO). The dielectric data were analyzed in terms of the molar orientational entropy increment induced by the probing electric field. It was found that the two polar liquids in the neat state reveal quite different molecular organization in terms of the dipole-dipole self-assembling: propylene carbonate exhibits a dipolar coupling of the head-totail type while in dimethyl sulfoxide one observes an extreme restriction of dipolar association in any form. In PC + DMSO mixtures, the disintegration of the dipolar ensembles of PC molecules takes place and the progress of that process is strictly proportional to the concentration of DMSO. The static permittivity of mixtures of such differently self-organized liquids exhibits a positive deviation from the additive rule and the deviation develops symmetrically within the concentration scale.
ACS Paragon Plus Environment
Page 2 of 29
Page 3 of 29
The Journal of Physical Chemistry
3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
INTRODUCTION Although the designing of liquid mixtures exhibiting the physicochemical properties assumed in advance is a real challenge for chemical engineering, this type of task is frequently undertaken by the chemical engineers. This is due to the natural needs of processes which are “fast, efficient and low-energy”. Besides, the most favorable would be the processes which are friendly for the environment, i.e. the chemicals used should be classified as “a green chemistry”. As the properties of any mixture of liquids are stored in the intermolecular interactions between the components, an importance and usefulness of the basic research are here obvious. Propylene carbonate (PC) and dimethyl sulfoxide (DMSO), the chemical structure of which is presented on Figure 1, are important representatives of reagents that satisfy the requirements of "green chemistry" and whose usefulness in many industries has been fully confirmed.1-5
Figure 1. The chemical structure of propylene carbonate (PC) and dimethyl sulfoxide (DMSO). Undoubtedly, more universal liquid is DMSO, the application of which extends from the electrochemistry to medicine.6-8 Particularly spectacular and extremely anomalous properties exhibit the mixtures of DMSO (m.p. = 18°C) and water for which a surprisingly low freezing point at about -40°C is measured for the molar fraction of DMSO of about 0.35 in the mixture.9,10 Propylene carbonate (m.p. = -49°C, b.p. = 242°C), in turn, is very suitable
ACS Paragon Plus Environment
The Journal of Physical Chemistry
4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
as an electrolyte solvent in lithium ion batteries11,12 or as a plasticizer for solid polymer electrolytes.13 Both solvents, PC and DMSO, are highly polar liquids what is connected mainly with high values of their molecular dipole moments (4.94 D14 for PC and 3.96 D15 for DMSO). However, the difference of about 1 D in the dipole moments seems to be not sufficient to explain a fairly large difference in the static permittivities ( ε S ) of these liquids ( ε S = 64.4 for PC and 46.7 for DMSO, at 25°C), the more that the ratio of their molar volumes (84.7 cm3/mol for PC and 71 cm3/mol for DMSO, at 25°C) works rather towards leveling the difference in the permittivities of the both liquids. Of course, an explanation of the permittivity difference can be made by the recognition of the type of self-assembling occurring between the molecular dipoles of PC and DMSO. Hence, one is able to identify the possible intermolecular entities which are formed in these liquids and influence the final value of their static permittivities. Unfortunately, the published experimental papers on this subject show large discrepancies in the assessment of the type of dipolar aggregation occurring in PC and DMSO. This assessment in the majority of the papers is based on the Kirkwood correlation factor ( g K ), the value of which is, however, quite difficult for credible determination. It stems from the fact that the factor g K depends mainly on the difference between the static ( ε S ) and high-frequency ( ε ∞ ) permittivities of studied liquid and there are serious experimental problems with precise determination of ε ∞ . The wider analysis of that important topic in molecular physics was presented in recent paper,16 and here we only briefly show the current state of research on the dipolar aggregation in liquid PC and DMSO. The experimental data published in the literature are particularly divergent in the case of PC: for available extreme experimental values of ε ∞ = 2.22 or 4.14,17 one obtains quite different image of dipolar association in that liquid. Basing on the above values of ε ∞ , the
ACS Paragon Plus Environment
Page 4 of 29
Page 5 of 29
The Journal of Physical Chemistry
5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
calculated Kirkwood correlation factor g K equals either to 1.23 (what points out for not too high but clear linear association of the head-to-tail type) or to 0.57 (strongly antiparallel association). A slightly smaller, but also confusing discrepancy concerns the dipolar association in DMSO,17 for which the extreme values of g K which can be found, are 0.52 or 1.04, however here, most published data are not far from g K = 1 .18-22 In this paper we analyze the data of the static permittivity of PC and DMSO, as well as their mixtures, in the whole range of concentrations and at different temperatures. The PC + DMSO mixtures are used in numerous physico-chemical processes, in particular as media for electrolytes for lithium batteries. So, knowledge of the dielectric properties of the tested liquids and the relationship of these characteristics with the type of occurring intermolecular interactions, is the basis for the design of liquid mixtures with suitable properties. It is obvious that such investigation requires a reliable method of analysis the static dielectric data in terms of the structure of the intermolecular entities which can be formed in studied liquid. As shown above, the Kirkwood correlation factor, due to high uncertainty in the choice of ε ∞ , cannot constitute a solid basis for the structural discussions. In this work the basis for such discussion is temperature derivative of the static permittivity,23 which reflects the actual orientational abilities of molecular dipoles in studied liquid. These abilities correspond directly to kind of the dipolar intermolecular entities existing in studied liquid.
EXPERIMENTAL SECTION Propylene carbonate (4-methyl-1,3-dioxolane-2-one), C4H6O3, and dimethyl sulfoxide, (CH3)2S=O, from Sigma-Aldrich, the both of purity 99.9%, were stored over molecular sieves (4 Å) for several weeks. At the time, they were placed in desiccator over silica gel. The measurements were performed for PC + DMSO mixtures in the whole concentration range.
ACS Paragon Plus Environment
The Journal of Physical Chemistry
6 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The solutions were prepared by weighting with an accuracy of ± 1·10-4 g. The standard uncertainty for the mole fraction determination was 2·10-4. The complex permittivity spectra were recorded with the use of an HP 4194A impedance/gain phase analyzer in the frequency range from 100 Hz to 5 MHz. The measurements were performed in the temperature range from 253.15 K to 353.15 K. At first, the samples were cooled down (approximately with 2 K/min) to 253 K and next the measurements were performed for increasing temperature. The temperature of the measuring cell was controlled with a “Scientific Instruments” device, model 9700, within ± 2·10-3 K. The details on the used experimental set-up can be found in recent paper.24 The standard uncertainty for the permittivity determination was 0.05.
RESULT AND DISCUSSION Figure 2 presents the real (a) and imaginary (b) parts of the dielectric spectra recorded at different temperatures for the mixture of PC + DMSO with the mole fraction xDMSO ≈ 0.9 , as an example. An apparent increase of the static permittivity, which is observed in the low frequency region of the real spectra (a), reflects the polarization effects on the electrodes of measuring cell due to ionic impurities present in liquids. The conduction of those residual ions causes the energy losses represented by the imaginary part (b) of the spectra. As can be seen in Figure 2, in our experiment one records the phase transition between the solid and liquid phases. In the used temperature range, that transition is observed for PC + DMSO mixtures with the mole fractions from the range: 0.6 ≤ xDMSO ≤1.0 , i.e. for the mixtures rich in DMSO.
ACS Paragon Plus Environment
Page 6 of 29
Page 7 of 29
The Journal of Physical Chemistry
7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 2. The real (a) and imaginary (b) parts of the dielectric spectra of PC + DMSO mixture with the mole fraction of xDMSO ≈ 0.9 , recorded in the solid and liquid phases of the mixture upon heating. Figure 3 presents the static permittivity of the mixtures of PC + DMSO as a function of their composition and temperature, obtained from analysis of the real part of the dielectric spectra (a). A sharp drop in the permittivity which occurs in several mixtures is due to the liquid-to-solid transition. The temperatures of the transitions allowed one to draw up a part of the phase diagram for the mixtures of PC + DMSO which, as depicted in Figure 4, is in a good consistency with m.p. of neat PC.25
Figure 3. Concentration and temperature dependences of the static permittivity of propylene carbonate + dimethyl sulfoxide solutions.
ACS Paragon Plus Environment
The Journal of Physical Chemistry
Page 8 of 29
8 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 4. The phase diagram for the mixtures of PC + DMSO. As mentioned above, the analysis of the measured static permittivity, ε S , and the evaluation of usefulness of that quantity in determination of the structure of dipolar liquids, will be based on temperature derivative of the permittivity, d ε S dT . In 1958, Fröhlich23 showed as the first, that this derivative is proportional to the change in entropy of dipolar liquid due to an orienting effect caused by the probing electric field of intensity E: ∆S (T ) E
2
≡
S (T , E ) − S0 (T ) E
2
=
ε 0 dε S 2 dT
(T ) ,
(1)
where S0 (T ) denotes the entropy in absence of the electric field, T is the absolute temperature and ε0 = 8.85 pF/m is the permittivity of free space. Since in the most cases an applying of electric field causes an ordering of molecular dipoles in liquid, the entropy increment ∆S is usually negative. Some exceptions may be encountered in the pre-transitional region of certain nematogenic liquids.26-28 Then, the prenematic antiparallel arrangement of dipoles can be partially destroyed by external electric field what leads to an increase of molecular disorder in these liquids, i.e. ∆S can change its sign to the positive. An important note on possible evolution of the increment ∆S with the temperature change, results directly from thermodynamically obvious principle, namely, that any type of the dipole-dipole assembling occurring in a given liquid enhances itself, when the temperature decreases. That is, in the case of linear dipolar association of the head-to tail type, the absolute
ACS Paragon Plus Environment
Page 9 of 29
The Journal of Physical Chemistry
9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
value of ∆S will increase with decreasing temperatures while the antiparallel association will lead to an opposite effect, namely, to decrease of ∆S . And only in very exceptional, mentioned above cases of liquid crystalline materials, the increment can attain zero or even can be a positive. Between these significantly different types of dipolar aggregation there is a natural place for dipolar liquids, in which, for various reasons, mostly for the steric ones, the aggregation is severely limited. Then, in principle, there are no reasons for ∆S to be temperature dependent.
Figure 5. Increment of the orientational entropy determined from eq 1 for the mixtures of propylene carbonate (PC) and dimethyl sulfoxide (DMSO) of different compositions of the mixtures and at different temperatures. Figure 5 presents temperature dependences of the entropy increment determined for solutions with different mole fractions of DMSO in PC. Immediately striking is significantly different behavior of the increment in the neat liquids. In the case of PC, we have undoubtedly faced with a phenomenon of the head-to-tail association of dipoles, while DMSO demonstrates, anyway as expected, the virtual absence of aggregation of the molecular dipoles.18-21 Comparison of these conclusions with those resulting from the theoretical calculations is somewhat difficult because the calculations mostly involve interactions between the isolated molecules.29 Then, an optimization of the structure of DMSO and PC dimers leads
ACS Paragon Plus Environment
The Journal of Physical Chemistry
10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
often to an antiparallel mutual orientation of the two molecules of the compounds.30,31 An explanation for that apparent contradiction with our experimental results can be found in the paper by Silva et al.32 The authors have used the Monte Carlo simulations to determine the structure and other thermodynamic properties of PC. As the main result of the paper is a finding that in the neat liquid state the electrostatic interactions lead the neighboring PC molecules to a preferential head-to-tail alignment. Next, an important result of the simulation refers to the situation in the gas phase. Here, the most energetically favorable is the antiparallel orientation of the dipolar molecules of the PC. So, our experimental results very well confirm the simulation results obtained by Silva et al. for neat liquid PC. However, there is some problem concerning the results shown in Figure 5. Namely, the increments ∆S were obtained by differentiation of the permittivity which was measured in the cell, the volume of which is virtually temperature independent. It means that with the change of temperature, changes itself also the number of dipoles in the measuring cell what can cause the apparent modifications in the orientational effects. Removing of those doubts is basically simple, just multiply the increment from Figure 5 by the molar volume ( VM ) of studied liquid at a given temperature: ∆S (T ) VM (T ) E 2 . After that, under consideration is the orientational effects related to one mole, this is the Avogadro number of dipoles. Figure 6 presents the increment of the orientational entropy per one mole of dipolar molecules of chosen solutions of PC + DMSO, as a function of temperature. In the molar approach, the increment of entropy obviously changed its value in comparison to that at constant volume, but now it reflects exclusively the current resultant dipole moment of the mole of molecules of studied liquid. As seen in Figure 6, the molar entropy increment in neat DMSO is decidedly independent of the temperature, thereby maintaining the previous conclusion on the virtual lack of dipolar aggregation in that liquid. As previously, the different behavior of PC in comparison to DMSO, is clearly seen in the figure. Certainly, here
ACS Paragon Plus Environment
Page 10 of 29
Page 11 of 29
The Journal of Physical Chemistry
11 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
we are dealing with the "head-to-tail" dipolar aggregation as the prevailing type of interaction in liquid PC.
Figure 6. Temperature dependence of the increment of the molar orientational entropy for several solutions of PC + DMSO. The molar volume of the mixtures were obtained from the data for neat components,33-35 assuming the additivity rule. If the slopes of temperature dependence of the molar entropy increment, presented in Figure 6, can be taken as some measure of an extension of the parallel association of molecular dipoles, then now we can display an evolution of that extension with increasing concentrations of DMSO in PC. Figure 7 shows dependence of the slopes (denoted as m) of the straight lines from Figure 6 (and others not shown on the figure), as a function of the mole fraction of DMSO in the mixtures with PC. As can be seen, the degree of the linear selfassociation of PC molecules decreases in a roughly linear way, as far as the mole fraction of DMSO increases. As a matter of fact, m represents the second derivative of the permittivity dependence on the temperature. The difference in temperature behavior of the entropy increment of neat DMSO and PC, clearly seen in Fig. 6, undoubtedly differentiates these two compounds from point of view the self-association ability of their molecules. However, used in this study the research method, despite its undoubtedly high sensitivity and uniqueness, does not provide quantitative assessment of the dipolar assembles. In particular, we do not know how extended is the self-
ACS Paragon Plus Environment
The Journal of Physical Chemistry
12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
association of PC molecules, and how many molecules, on average, take part in that process. Obtaining such quantitative information requires the use of real structural pattern as a reference. Fig. 8 presents a comparison of temperature dependences of the molar entropy increments of studied DMSO and PC as well as the dependences for two compounds which can be taken here as kind of references: a liquid secondary amide, N-methylacetamide (NMA), which strongly self-associates in chains, and n-pentylcyanobiphenyl (5CB), which belong to the most antiparallel dimerized liquid.
Figure 7. The slops (m) of temperature dependence of the increment of molar orientational entropy as a function of the mole fraction of DMSO dissolved in PC.
Figure 8. Temperature dependences of the increments of molar orientational entropy of neat DMSO and PC. For comparison are presented dependences for two significantly selfassembled compounds: N-methylacetamide (NMA),36 the molecules of which form strongly elongated hydrogen-bonded chains (head-to-tail) and n-pentylcyanobiphenyl (5CB),16 dipolar liquid where the antiparallel dimers are strongly dominating intermolecular entities. Molar volumes of NMA were obtained from the data.37
ACS Paragon Plus Environment
Page 12 of 29
Page 13 of 29
The Journal of Physical Chemistry
13 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Notwithstanding the significant difference in the energy of the dipolar interactions and the hydrogen bonds, Figure 8 shows that the dipolar self-association in liquid PC is of the heat-to tail type. At the end of the work, seems to be interesting to see, how the static permittivity behaves from the point of view of its additivity, in the liquid mixtures of such fairly well defined intermolecular interactions. The result can be interesting for both designers of liquid mixtures, who usually apply the rule of additivity of permittivity, as well as for researchers who are looking for the relationship between the dipolar interactions and the non-additive behavior of the permittivity in liquid mixtures.38,39
Figure 9. The concentration dependences of (a) the static permittivity and (b) its deviation from the additivity (eq 2) in the mixtures of PC + DMSO, at three chosen (from Figure 3) temperatures. The dashed lines in (a) represent a supposed additive behavior of the permittivity in the mixtures. Figure 9a presents dependence of the static permittivity of PC + DMSO mixtures on the mole fraction of DMSO, at chosen (from Figure 3) three temperatures. Part b of the figure presents the permittivity deviation from additivity ( ∆ε S ):
∆ε S = ε S − (1 − xDMSO ) ε SPC + xDMSOε SDMSO ,
ACS Paragon Plus Environment
(2)
The Journal of Physical Chemistry
14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
where ε S denotes the static permittivity measured at the given temperature for solution where the mole fraction of DMSO is equal xDMSO , while ε SPC and ε SDMSO are the permittivities of neat components of the mixture, measured at the same temperature. As is apparent from Figure 9b, the static permittivity measured for the mixtures of PC + DMSO shows a positive deviation from the additivity rule and the maximum of deviation corresponds roughly to the PC : DMSO molecules ratio of 1:1, and the value of the deviation at the maximum attains about 5% of the permittivity value, depending somewhat on the temperature.
CONCLUSIONS The following conclusions, resulting from the presented above experimental data, seem to be important. First of all, it was shown that the increment of the molar orientational entropy and its temperature behavior allow one for much unambiguous determination of the molecular structure of dipolar liquids than the Kirkwood correlation factor with its problems in reliable determination of the high-frequency permittivity ε∞. On the basis of the experimental dielectric data obtained for two liquids of high technical and scientific impact, namely, propylene carbonate and dimethyl sulfoxide, it was found that the molecular dipoles in the first liquid exhibit a tendency to the self-assembling in the parallel, head-to-tail way, while in the other liquid the dipolar self-assembling is extremely restricted. Experimental identification the way of the molecular aggregation in PC, which strongly support the result of the Monte Carlo simulations,32 allows one to understanding of the significantly increased permittivity of that liquid in comparison with that of DMSO. The studies showed that in PC + DMSO solutions the self-assembles composed of PC molecules gradually disintegrate as the concentration of DMSO is increasing. And finally, it was found that in the mixtures of differently self-organized liquids, the static permittivity exhibits a positive deviation from the additivity rule and, in the
ACS Paragon Plus Environment
Page 14 of 29
Page 15 of 29
The Journal of Physical Chemistry
15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
concentration scale, that deviation (defined by eq 2) is more or less symmetrical. The deviation, in its maximum, reaches approximately 5% of the value of the measured static permittivity (at 303 K).
ACS Paragon Plus Environment
The Journal of Physical Chemistry
Page 16 of 29
16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
REFERENCES (1)
Parker, H. L.; Sherwood, J.; Hunt, A. J.; Clark, J. H. Cyclic Carbonates as Green
Alternative Solvents for the Heck Reaction. ACS Sustainable Chem. Eng. 2014, 2, 1739−1742. (2) Verevkin, S. P.; Emel'yanenko, V. N.; Bayardon, J.; Schäffner, B.; Baumann, W.; Börner, A. Asymmetric Hydrogenation of Nonfunctionalized Olefins in Propylene Carbonate−Kinetic or Thermodynamic Control? Ind. Eng. Chem. Res. 2012, 51, 126−132. (3) Xu, D.; Wang, Z. L.; Xu, J. J.; Zhang, L. L.; Zhang, X. B. Novel DMSO-Based Electrolyte for High Performance Rechargeable Li−O2 Batteries. Chem. Commun. 2012, 48, 6948−6950. (4) Kötz, R.; Carlen, M. Principles and Applications of Electrochemical Capacitors.
Electrochim. Acta 2000, 45, 2483−2498. (5) Conway, B. E. Electrochemical Supercapacitors; Kluwer Academic/Plenum Publishers: New York, 1999. (6) Jacob, S. W.; De La Torre, J. C. Dimethyl Sulfoxide (DMSO) in Trauma and Disease; CRC Press: Boca Raton, 2015. (7) Capriotti, K.; Capriotti, J. A. Dimethyl Sulfoxide: History, Chemistry, and Clinical Utility in Dermatology. J. Clin. Aesthet. Dermatol. 2012, 5, 24–26. (8) Yu, Z.-W.; Quinn, P. J. Dimethyl sulfoxide: A Review of its Applications in Cell Biology. Biosci. Rep. 1994, 14, 259−281. (9) Rasmussen,
D.
H.;
Mackenzie,
A.
P.
Phase
Diagram
for
the
System
Water−Dimethylsulphoxide. Nature 1968, 220, 1315−1317. (10) Płowaś, I.; Świergiel, J.; Jadżyn, J. Relative Static Permittivity of Dimethyl Sulfoxide + Water Mixtures. J. Chem. Eng. Data 2013, 58, 1741−1746. (11) Bhatt, M. D.; O’Dwyera, C. Solid Electrolyte Interphases at Li-Ion Battery Graphitic Anodes Inpropylene Carbonate (PC)-Based Electrolytes Containing FEC, LiBOB, and LiDFOB as Additives. Chem. Phys. Lett. 2015, 618, 208–213. (12) Richardson, P. M.; Voice, A. M.; Ward, I. M. Pulsed-Field Gradient NMR Self Diffusion and Ionic Conductivity Measurements for Liquid Electrolytes Containing LiBF4 and Propylene Carbonate. Electrochim. Acta 2014, 130, 606–618. (13) Das, S.; Ghosh, A. Ionic Conductivity and Dielectric Permittivity of PEO−LiClO4 Solid Polymer Electrolyte Plasticized with Propylene Carbonate. AIP Advances 2015, 5, 027125.
ACS Paragon Plus Environment
Page 17 of 29
The Journal of Physical Chemistry
17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
(14) Kempa, R.; Lee, W. H. The Dipole Moments of Some Cyclic Carbonates. J. Chem.
Soc. 1958, 1936−1938. (15) Driezler, H.; Dendl, G. Rotationsspektrum, r0-Struktur und Dipolmoment von Dimethylsulfoxyd. Naturforsch. A 1964, 19, 512−514. (16) Świergiel, J.; Płowaś, I.; Jadżyn, J. On Investigation of Aggregation of Molecular Dipoles in Liquids. J. Mol. Liq. 2016, 220, 879−882. (17) Barthel, J.; Bachhuber, K.; Buchner, R.; Gill, J. B.; Kleebauer, M. Dielectric Spectra of Some Common Solvents in the Microwave Region. Dipolar Aprotic Solvents and Amides.
Chem. Phys. Lett. 1990, 167, 62−66. (18) Prestbo, E. W.; McHale, J. L. Static Dielectric Constants and Kirkwood Correlation Factors of Dimethyl Sulfoxide/Carbon Tetrachloride Solutions. J. Chem. Eng. Data 1984, 29, 387−389. (19) Kaatze, U.; Pottel, R.; Schaefer, M. Dielectric Spectrum of Dimethyl Sulfoxide/Water Mixtures as a Function of Composition. J. Phys. Chem. 1989, 93, 5623−5627. (20) Vechi, S. M.; Skaf, M. S. Collision-Induced Effects on the Dielectric Properties of Liquid Dimethylsulfoxide. J. Braz. Chem. Soc. 2002, 13, 583−591. (21) Sengwa, R. J.; Sankhla, S.; Khatri, V. Dielectric Characterization and Molecular Interaction Behaviour in Binary Mixtures of Amides with Dimethylsulphoxide and 1,4Dioxane. J. Mol. Liq. 2010, 151, 17−22. (22) Ritzoulis, G. Excess Properties of the Binary Liquid Systems Dimethylsulfoxide + Isopropanol and Propylene Carbonate + Isopropanol. Can. J. Chem. 1989, 67, 1105−1108. (23) Fröhlich, H. Theory of Dielectrics, 2nd ed.; Clarendon Press: Oxford, 1958. (24) Świergiel, J.; Jadżyn, J. Static Dielectric Permittivity of Homologous Series of Liquid Cyclic Ethers 3n-crown-n, n = 4 to 6. J. Chem. Eng. Data 2012, 57, 2271−2274. (25) Ding, M. S.; Xu, K.; Jow, T. R. Liquid-Solid Phase Diagrams of Binary Carbonates for Lithium Batteries. J. Electrochem. Soc. 2000, 147, 1688−1694. (26) Jadżyn, J.; Czechowski, G. Prenematic Behavior of the Electric-Field-Induced Increment of the Basic Thermodynamic Quantities of Isotropic Mesogenic Liquids of Different Polarity. J. Phys. Chem. B 2007, 111, 3727−3729. (27) Jadżyn, J.; Czechowski, G.; Déjardin, J.-L. Dynamics of the Self-Assembling of Mesogenic Molecules in the Prenematic Region of Isotropic Liquid. J. Phys. Chem. B 2008,
112, 4948−4952.
ACS Paragon Plus Environment
The Journal of Physical Chemistry
18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
(28) Jadżyn, J.; Sokołowska, U.; Déjardin, J.-L. Temperature Behavior of the Electric Field-Induced Entropy Increment within a Homologous Series of Nematogenic Compounds.
J. Phys. Chem. B 2008, 112, 9050–9052. (29) Jensen, J. H.; Gordon, M. S. An Approximate Formula for the Intermolecular Pauli Repulsion Between Closed Shell Molecules. II. Application to the Effective Fragment Potential Method. J. Chem. Phys. 1998, 108, 4772−4782. (30) Varnali, T. Associated Species of Dimethylsulfoxide: Semiempirical Modeling. Struct.
Chem. 1996, 7, 111−118. (31) Kollipost, F.; Hesse, S.; Lee, J. J.; Suhm, M. A. Dimers of Cyclic Carbonates: Chirality Recognition in Battery Solvents and Energy Storage. Phys. Chem. Chem. Phys.
2011, 13, 14176−14182. (32) Silva, L. B.; Gomide Freitas, L. C. Structural and Thermodynamic Properties of Liquid Ethylene Carbonate and Propylene Carbonate by Monte Carlo Simulations. J. Mol.
Struct.: THEOCHEM 2007, 806, 23−34. (33) Moumouzias, G.; Ritzoulis, G. Viscosities and Densities for Propylene Carbonate + Toluene at 15, 20, 25, 30, and 35°C. J. Chem. Eng. Data 1992, 37, 482−483. (34) Barthel, J.; Neueder, R.; Roch, H. Density, Relative Permittivity, and Viscosity of Propylene Carbonate + Dimethoxyethane Mixtures from 25°C to 125°C. J. Chem. Eng. Data
2000, 45, 1007−1011. (35) Grande, M. C.; Garcia, M.; Marschoff, C. M. Density and Viscosity of Anhydrous Mixtures of Dimethylsulfoxide with Acetonitrile in the Range (298.15 to 318.15) K. J. Chem.
Eng. Data 2009, 54, 652−658. (36) Świergiel, J.; Jadżyn, J. Fractional Stokes-Einstein-Debye Relation and Orientational Entropy Effects in Strongly Hydrogen-Bonded Liquid Amides. Phys. Chem. Chem. Phys.
2011, 13, 3911−3916. (37) Nallani, S.; Boodida, S.; Tangeda, S. J. Density and Speed of Sound of Binary Mixtures of N-Methylacetamide with Ethyl Acetate, Ethyl Chloroacetate, and Ethyl Cyanoacetate in the Temperature Interval (303.15 to 318.15) K. J. Chem. Eng. Data 2007, 52, 405−409. (38) Iglesias, T. P. On the Definition of the Excess Permittivity of a Fluid Mixture.
J. Chem. Thermodyn. 2008, 40, 1038−1039. (39) Iglesias, T. P.; Reis, J. C. R. Separating the Contributions of the Volume Change upon Mixing, Permittivity Contrast and Molecular Interactions in the Excess Relative Permittivity of Liquid Mixtures. Phys. Chem. Chem. Phys. 2015, 17, 13315−13322.
ACS Paragon Plus Environment
Page 18 of 29
Page 19 of 29
The Journal of Physical Chemistry
19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
TOC GRAPHICS
ACS Paragon Plus Environment
The Journal of Physical Chemistry
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 1. The chemical structure of propylene carbonate (PC) and dimethyl sulfoxide (DMSO). 80x43mm (300 x 300 DPI)
ACS Paragon Plus Environment
Page 20 of 29
Page 21 of 29
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
Figure 2. The real (a) and imaginary (b) parts of the dielectric spectra of PC + DMSO mixture with the mole fraction of xDMSO ≈ 0.9, recorded in the solid and liquid phases of the mixture upon heating. 138x254mm (300 x 300 DPI)
ACS Paragon Plus Environment
The Journal of Physical Chemistry
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 3. Concentration and temperature dependences of the static permittivity of propylene carbonate + dimethyl sulfoxide solutions. 119x109mm (300 x 300 DPI)
ACS Paragon Plus Environment
Page 22 of 29
Page 23 of 29
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
Figure 4. The phase diagram for the mixtures of PC + DMSO. 100x66mm (300 x 300 DPI)
ACS Paragon Plus Environment
The Journal of Physical Chemistry
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 5. Increment of the orientational entropy determined from eq 1 for the mixtures of propylene carbonate (PC) and dimethyl sulfoxide (DMSO) of different compositions of the mixtures and at different temperatures. 127x110mm (300 x 300 DPI)
ACS Paragon Plus Environment
Page 24 of 29
Page 25 of 29
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
Figure 6. Temperature dependence of the increment of the molar orientational entropy for several solutions of PC + DMSO. The molar volume of the mixtures were obtained from the data for neat components,33-35 assuming the additivity rule. 115x80mm (300 x 300 DPI)
ACS Paragon Plus Environment
The Journal of Physical Chemistry
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 7. The slops (m) of temperature dependence of the increment of molar orientational entropy as a function of the mole fraction of DMSO dissolved in PC. 124x97mm (300 x 300 DPI)
ACS Paragon Plus Environment
Page 26 of 29
Page 27 of 29
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
Figure 8. Temperature dependences of the increments of molar orientational entropy of neat DMSO and PC. For comparison are presented dependences for two significantly self-assembled compounds: Nmethylacetamide (NMA),36 the molecules of which form strongly elongated hydrogen-bonded chains (headto-tail) and n-pentylcyanobiphenyl (5CB),16 dipolar liquid where the antiparallel dimers are strongly dominating intermolecular entities. Molar volumes of NMA were obtained from the data.37 122x87mm (300 x 300 DPI)
ACS Paragon Plus Environment
The Journal of Physical Chemistry
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Figure 9. The concentration dependences of (a) the static permittivity and (b) its deviation from the additivity (eq 2) in the mixtures of PC + DMSO, at three chosen (from Figure 3) temperatures. The dashed lines in (a) represent a supposed additive behavior of the permittivity in the mixtures. 161x167mm (300 x 300 DPI)
ACS Paragon Plus Environment
Page 28 of 29
Page 29 of 29
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
TOC 50x37mm (300 x 300 DPI)
ACS Paragon Plus Environment
