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Self-diffusion of molecules in ethylene glycol solutions of dimethyl sulfoxide
Journal of Molecular Liquids 248 (2017) 898–901
Contents lists available at ScienceDirect
Journal of Molecular Liquids journal homepage: www.elsevier.com/locate/molliq
Self-diffusion of molecules in ethylene glycol solutions of dimethyl sulfoxide M.N. Rodnikova a,⁎, Z.Sh. Idiyatullin b, J. Barthel c, I.A. Solonina a, D.A. Sirotkin a a b c
Kurnakov Institute of General and Inorganic Chemistry, RAS, Moscow, Russia Kazan National Research Technological University, Kazan, Russia Institute of Theoretical and Physical Chemistry, Regensburg, Germany
a r t i c l e
i n f o
Article history: Received 14 September 2017 Received in revised form 13 October 2017 Accepted 24 October 2017 Available online 26 October 2017 Keywords: Self-diffusion coefficients Ethylene glycol Dimethylsulfoxide Solution Hexamethylphosphoric triamide
a b s t r a c t The self-diffusion coefficients of dimethylsulfoxide (DMSO) and ethylene glycol (EG) are measured using spinecho approach on protons in a wide concentration range of ethylene glycol DMSO solution in the temperature range 30 °C–70 °C. The activation energies of the corresponding self-diffusion processes are calculated. The results are discussed as interactions and structural changes in the system EG-DMSO and compared with similar results on the study of the EG - hexamethylphosphoric triamide (HMPA) system. © 2017 Elsevier B.V. All rights reserved.
1. Introduction Dimethyl sulfoxide (DMSO) is a solvent widely used in studies of cell biology, cryobiology, pharmacology and chemical practice [1]. Its aqueous solutions are studied by various methods. It was of interest to investigate solutions of DMSO in EG solvent with a spatial network of hydrogen bonds [2], and also to compare the results with the characteristics of the EG-HMPA system [3]. The DMSO molecule is amphiphilic. Its hydrophobic part is made up of two CH3-groups, the hydrophilic group is −S = O. It has a lower electron donor, lower dipole moment and less hydrophobicity than the HMPA molecule. The ratio of hydrophobic and hydrophilic parts in the DMSO molecule is 2 / 29.8 = 0.07, and in the HMPA molecule ratio is 6 / 38.8 = 0.15, i.е. 2 times more than in the DMSO molecule (hydrophobicity is associated with the number of CH3-groups, hydrophilicity with an electron-donating number according to Gutman [4]). Of course, there are more factors affecting the characteristics of solutions of these substances, in particular, volume and structure of the molecule. Nevertheless, this rough comparative assessment of the hydrophobicity of these substances is characteristic. Hydrophobic effects were recorded in the aqueous systems of these nonelectrolytes, and, in the H2ODMSO system, at lower non-electrolyte concentrations than in the H2O-HMPA system [5–8].
⁎ Corresponding author. E-mail address: [email protected] (M.N. Rodnikova).
https://doi.org/10.1016/j.molliq.2017.10.113 0167-7322/© 2017 Elsevier B.V. All rights reserved.
The physical and physicochemical properties of DMSO and HMPA are shown in Table 1 [9–14]. EG as well as water has a spatial network of H-bonds, but less perfect and more rigid [2]. Solvophobic effects can be expected in ethylene glycol solutions of non-electrolytes [15]. Earlier we have investigated the EGHMPA system using the spin-echo approach on protons in the range of low concentrations of HMPA in the temperature range 30 °C – 60 °C. A decrease of the mobility of EG molecules in the range of ~7 mol% of HMPA was explained by solvophobic effects in the EG-HMPA system [3]. In the present study on the EG-DMSO system comparison is made in the range of small concentrations of non-electrolyte, as well as that on of the mobilities of pure HMPA and DMSO molecules. 2. Experimental The self-diffusion coefficients of the DMSO and EG molecules were measured using the spin-echo approach with a pulse gradient of magnetic field (Gt) on a Tesla-BS-567A NMR 1H high-resolution Fourier transform spectrometer (100 MHz) [16] at the Kazan National Research Technological University. The procedure for measuring the selfdiffusion coefficient included recording the spectra at different gradients of the magnetic field. Each spectrum is a Fourier transform of half of spinecho. The registration of the corresponding lines Ai in the spectrum and their processing in the coordinates lnAi – Gt2i allowed us to determine the self-diffusion coefficient from the slope of the approximating line. DMSO (99%) and EG (99%) of the brand “Acros” were used without preliminary purification. Samples were prepared gravimetrically. All
M.N. Rodnikova et al. / Journal of Molecular Liquids 248 (2017) 898–901 Table 1 Physico-chemical characteristics of investigated substances [9].
М μ, D Тm.p., °С Тb.p., °С ρ (25 °С), kg/m3·10−3 η (25 °С), Pa·с·103
DMSO
EG
HMPA
78 3,96 [10] 18,5 189 1.0955 2 [12]
62 2,88[10] −12,9 197 1113 16,16 [13]
179 5,24 [11] 7 230 0,879 3147 [14]
Table 2 Self-diffusion coefficients (D·10−5, cm2/c) EG and DMSO molecules in concentration range 0–50% DMSO and temperature range 30.6 °С – 70°С. DMSO (mol%)
EG EG EG EG DMSO DMSO DMSO DMSO 30,6°С 40,0°С 50,5°С 70,0°С 30,6°С 40,0°С 50,5°С 70,0°С
0 0,44 1,19 2,78 5 6,92 9,28 14,42 28,57 49,03 100
0,120 0,120 0,121 0,128 0,133 0,137 0,149 0,168 0,226 0,296
0,171 0,173 0,173 0,180 0,186 0,193 0,203 0,222 0,287 0,395
0,242 0,242 0,249 0,261 0,270 0,279 0,288 0,317 0,398 0,528
0,428 0,448 0,440 0,453 0,466 0,477 0,496 0,534 0,652 0,808
0,112 0,132 0,137 0,140 0,160 0,172 0,232 0,330 0,815
0,173 0,181 0,198 0,206 0,229 0,294 0,427 0,971
0,268 0,275 0,284 0,296 0,325 0,408 0,558 1179
0,428 0,459 0,477 0,492 0,542 0,661 0,847 1660
operations were carried out in a dry chamber in a stream of dry nitrogen. The samples were thermostated in the spectrometer sensor at a given temperature with an accuracy of ± 1 °C. The error of the selfdiffusion coefficient did not exceed 5%. 3. Results The experimental data of the self-diffusion coefficients of DMSO and EG molecules are presented in Table 2 and in Fig. 1, their calculated
899
Table 3 Activation energies of the self-diffusion process of EG and DMSO at different concentrations DMSO in temperature range 30.6 °С – 70 °С. DMSO (mol%)
Ea, Kcal/mol EG
0 0,44 1,19 2,78 5 6,92 9,28 14,42 28,57 49,03 100
6,68 6,9 6,76 6,65 6,61 6,57 6,36 6,14 5,64 5,25
DMSO
6,31 6,46 6,43 5,98 6,07 5,56 4,95 3,75
activation energies of the self-diffusion processes of DMSO and EG molecules in the temperature range 30 °C – 70 °C are given in Table 3. 4. Discussion For technical reasons, we could not perform measurements at lower temperatures than 30 °C; DMSO has a melting point 18.4 °C. At all temperatures, the self-diffusion coefficients of the DMSO and EG molecules are increasing monotonically with increasing DMSO concentration in the solution. Only at 30 °C, the self-diffusion coefficient of EG molecules in the solution of the lowest studied concentration (0.44 mol% DMSO) does not change its value in comparison with pure EG. The device does not register a smaller concentration. The activation energies of the self-diffusion process are decreasing monotonically. A decrease of the mobility of solvent molecules (EG) at low concentrations of DMSO, accompanying solvophobic solvation [15], was not recorded by this method. The evidence for the existence of solvophobic effects in the EG-DMSO system was shown only in paper [17] on the basis of the concentration dependence of the volume properties - the minimum
Fig. 1. Self-diffusion coefficients (D·10−5, cm2/c) EG and DMSO molecules in concentration range 0–50% DMSO и temperature range 30.6°С – 70 °С.
900
M.N. Rodnikova et al. / Journal of Molecular Liquids 248 (2017) 898–901
Table 4 Comparison of molecular mobility of DMSO, HMPA and EG in individual liquids in temperature range 30 °С – 50 °С. T, °С
D·105, cm2/s
30 40 50
DMSO 0,815 0,971 1179
HMPA 0,344 0,425 0,497
EG 0,120 0,171 0,242
30÷50
Ea, Kcal/mol 3,62
3,86
6,90
effects of tetramethylurea (TMU) are found in aqueous and ethylene glycol solutions of this substance [22]. 5. Conclusions
molar-partial volume of DMSO at very low concentrations ~ 2 mol% DMSO. The hydrophobic part of the DMSO molecule is relatively small. The high heats of mixing DMSO with EG indicate a strong chemical interaction in the system leading to the formation of compounds 1:2 and 1:1 (phase diagram of the EG-DMSO system [18] and quantum chemical calculations [19]). It is interesting to compare the obtained results with the analogous data of the EG-HMPA system obtained by us earlier [3]. In Table 4 there are the data of self-diffusion coefficients in individual liquids. Fig. 2 shows the concentration dependences of the self-diffusion coefficients of EG and DMSO molecules in the EG-DMSO system and of EG and HMPA molecules in the EG-HMPA system at ~40 °C in the concentration range up to 16 mol%. In the EG-DMSO system, we can see monotonous increase of the self-diffusion coefficient of EG and DMSO molecules. We can see the minimum values of self-diffusion coefficients of HMPA and EG at a concentration in the range of ~ 7 mol% of HMPA in the EG-HMPA system. Thus, solvophobic effects are noticeable in the EG-HMPA system, and there are no solvophobic effects in the EG-DMSO system. A greater hydrophobicity/hydrophilicity ratio is confirmed of the HMPA molecule than of the DMSO molecule, which we proposed as a comparative assessment of the hydrophobicity (solvophobicity). Let us recall that the volume and structure of the non-electrolyte molecule play an essential role in the comparison. So when comparing the hydrophobicity of tetrahydrofuran (THF) and dioxane (DO), the ratios of the hydrophobic/hydrophilic parts of the molecule are almost equal: 4 (CH2)/20 = 0.2 for THF and 4 (CH 2)/14.8 = 0.27 for DO, but the composition and the structure of these molecules are completely different. Therefore, solvophobic effects were observed in an ethylene glycol solutions of THF [20], and no solvophobic effects in ethylene glycol solutions of DO [21]. Solvophobic
The system EG-DMSO was studied in the temperature range 30–70 °C using spin-echo approach on protons. A monotonous increase of mobility of EG and DMSO molecules increasing DMSO concentration in solution is observed; solvophobic effects are not detected. Comparison is made with the EG-HMPA system, in which solvophobic effects were recorded. The difference between these systems is explained by the greater hydrophobic component of the HMPA molecule, estimated by the ratio of the number of hydrophobic CH3-groups in the molecule to its Gutman electrondonating ability [4]. The work was carried out within the framework of the state assignment of IGIC RAS in the frame of fundamental scientific research with financial support of the Russian Foundation for Basic Research (Grants 15-03-04007 and 16-03-00897). References [1] D. Banik, N. Kundu, J. Kuchlyan, et al., J. Chem. Phys. (2015)https://doi.org/10.1063/ 1.4906541 (V.142. P.054505 and references in this article). [2] M.N. Rodnikova, Russ. J. Phys. Chem. A 67 (1993) 275. [3] Z.Sh. Idiatullin, I.A. Solonina, M.N. Rodnikova, D.A. Sirotkin, Russ. J. Phys. Chem. A 91 (8) (2017) 1426, https://doi.org/10.7868/S0044453717080131. [4] V. Gutman, “Chemistry of Coordination Compounds in Non-aqueous Solutions” M. Izd-vo “Mir”, 1971. [5] A.K. Soper, A. Luzar, J. Phys. Chem. 100 (1996) 1357, https://doi.org/10.1021/ jp951783r. [6] M.N. Rodnikova, Yu.A. Zakharova, I.A. Solonina, D.A. Sirotkin, Russ. J. Phys. Chem. A 86 (2012) 993. [7] G.I. Egorov, D.M. Makarov, Russ. J. Phys. Chem. A 83 (2009) 805. [8] J.T.W. Lai, F.W. Lau, D. Robb, et al., J. Solut. Chem. 24 (1995) 89. [9] Acros Organics. Catalog of Fine Chemicals. (Vol. 2002–2003). [10] O.Ya. Osipov, V.I. Minkin, A.D. Granovsky, Handbook on Dipole Moments, M.: Publ. Higher School, 1971. [11] J.Y. Gal, C. Moliton-Bouchetout, Bull. Soc. Chim. Fr. (1973) 464. [12] Ch. Wohlfarth, in: M.D. Lechner (Ed.), Landolt-Börnstein-Group IV Physical Chemistry 25: Physical Chemistry, Springer-Verlag, Berlin Heidelberg, 2009https://doi. org/10.1007/978-3-540-75486-2. [13] CRC Handbook of Chem. Phys.74th ed. (1993–1994) [14] Yu.M. Kessler, M.G. Fomicheva, N.M. Alpatova, V.P. Emelin, Russ. J. Eng. Chem. 13 (1972) 517. [15] M.N. Rodnikova, Structural Self-organization in Solutions and at the Interface of Phases(M. Publ. URSS C.151) 2008. [16] V.D. Fedotov, Yu.F. Zuev, V.P. Archipov, Z.Sh. Idiyatullin, Appl. Magn. Reson. 11 (1996) 7.
Fig. 2. Concentration dependences of self-diffusion coefficients of EG and DMSO molecules in system EG - DMSO and EG and HMPA in system EG - HMPA.
M.N. Rodnikova et al. / Journal of Molecular Liquids 248 (2017) 898–901 [17] G.I. Egorov, D.M. Makarov, Russian Chemistry and Chemical Technology, Vol. 54, 2011 65. [18] I.A. Solonina, M.N. Rodnikova, M.R. Kiselev, A.V. Khoroshilov, Russ. J. Phys. Chem. A (2018) (in press). [19] R.A. Vergenz, I. Yazji, C. Whittington, J. Daw, K.T. Tran, J. Am. Chem. Soc. l25 (40) (2003) 12318, https://doi.org/10.1021/ja036516a. [20] M.N. Rodnikova, Yu.A. Zakharova, D.B. Kayumova, I.A. Solonina, Russ. J. Phys. Chem. A 84 (2010) 518.
901
[21] D.B. Kayumova, M.N. Rodnikova, Yu.A. Zakharova, T.M. Valkovskaya, N.V. Kiruta, M.A. Gunina, Abstracts of the report at the 9th Kurnakov meeting on physical and chemical analysis, Perm, Vol. 99, 2010. [22] M.N. Rodniokova, F.M. Samigullin, J. Barthel, D.B. Kaumova, J. Phys. Chem. (Russ.) 78 (N2) (2004) 376.
Contents lists available at ScienceDirect
Journal of Molecular Liquids journal homepage: www.elsevier.com/locate/molliq
Self-diffusion of molecules in ethylene glycol solutions of dimethyl sulfoxide M.N. Rodnikova a,⁎, Z.Sh. Idiyatullin b, J. Barthel c, I.A. Solonina a, D.A. Sirotkin a a b c
Kurnakov Institute of General and Inorganic Chemistry, RAS, Moscow, Russia Kazan National Research Technological University, Kazan, Russia Institute of Theoretical and Physical Chemistry, Regensburg, Germany
a r t i c l e
i n f o
Article history: Received 14 September 2017 Received in revised form 13 October 2017 Accepted 24 October 2017 Available online 26 October 2017 Keywords: Self-diffusion coefficients Ethylene glycol Dimethylsulfoxide Solution Hexamethylphosphoric triamide
a b s t r a c t The self-diffusion coefficients of dimethylsulfoxide (DMSO) and ethylene glycol (EG) are measured using spinecho approach on protons in a wide concentration range of ethylene glycol DMSO solution in the temperature range 30 °C–70 °C. The activation energies of the corresponding self-diffusion processes are calculated. The results are discussed as interactions and structural changes in the system EG-DMSO and compared with similar results on the study of the EG - hexamethylphosphoric triamide (HMPA) system. © 2017 Elsevier B.V. All rights reserved.
1. Introduction Dimethyl sulfoxide (DMSO) is a solvent widely used in studies of cell biology, cryobiology, pharmacology and chemical practice [1]. Its aqueous solutions are studied by various methods. It was of interest to investigate solutions of DMSO in EG solvent with a spatial network of hydrogen bonds [2], and also to compare the results with the characteristics of the EG-HMPA system [3]. The DMSO molecule is amphiphilic. Its hydrophobic part is made up of two CH3-groups, the hydrophilic group is −S = O. It has a lower electron donor, lower dipole moment and less hydrophobicity than the HMPA molecule. The ratio of hydrophobic and hydrophilic parts in the DMSO molecule is 2 / 29.8 = 0.07, and in the HMPA molecule ratio is 6 / 38.8 = 0.15, i.е. 2 times more than in the DMSO molecule (hydrophobicity is associated with the number of CH3-groups, hydrophilicity with an electron-donating number according to Gutman [4]). Of course, there are more factors affecting the characteristics of solutions of these substances, in particular, volume and structure of the molecule. Nevertheless, this rough comparative assessment of the hydrophobicity of these substances is characteristic. Hydrophobic effects were recorded in the aqueous systems of these nonelectrolytes, and, in the H2ODMSO system, at lower non-electrolyte concentrations than in the H2O-HMPA system [5–8].
⁎ Corresponding author. E-mail address: [email protected] (M.N. Rodnikova).
https://doi.org/10.1016/j.molliq.2017.10.113 0167-7322/© 2017 Elsevier B.V. All rights reserved.
The physical and physicochemical properties of DMSO and HMPA are shown in Table 1 [9–14]. EG as well as water has a spatial network of H-bonds, but less perfect and more rigid [2]. Solvophobic effects can be expected in ethylene glycol solutions of non-electrolytes [15]. Earlier we have investigated the EGHMPA system using the spin-echo approach on protons in the range of low concentrations of HMPA in the temperature range 30 °C – 60 °C. A decrease of the mobility of EG molecules in the range of ~7 mol% of HMPA was explained by solvophobic effects in the EG-HMPA system [3]. In the present study on the EG-DMSO system comparison is made in the range of small concentrations of non-electrolyte, as well as that on of the mobilities of pure HMPA and DMSO molecules. 2. Experimental The self-diffusion coefficients of the DMSO and EG molecules were measured using the spin-echo approach with a pulse gradient of magnetic field (Gt) on a Tesla-BS-567A NMR 1H high-resolution Fourier transform spectrometer (100 MHz) [16] at the Kazan National Research Technological University. The procedure for measuring the selfdiffusion coefficient included recording the spectra at different gradients of the magnetic field. Each spectrum is a Fourier transform of half of spinecho. The registration of the corresponding lines Ai in the spectrum and their processing in the coordinates lnAi – Gt2i allowed us to determine the self-diffusion coefficient from the slope of the approximating line. DMSO (99%) and EG (99%) of the brand “Acros” were used without preliminary purification. Samples were prepared gravimetrically. All
M.N. Rodnikova et al. / Journal of Molecular Liquids 248 (2017) 898–901 Table 1 Physico-chemical characteristics of investigated substances [9].
М μ, D Тm.p., °С Тb.p., °С ρ (25 °С), kg/m3·10−3 η (25 °С), Pa·с·103
DMSO
EG
HMPA
78 3,96 [10] 18,5 189 1.0955 2 [12]
62 2,88[10] −12,9 197 1113 16,16 [13]
179 5,24 [11] 7 230 0,879 3147 [14]
Table 2 Self-diffusion coefficients (D·10−5, cm2/c) EG and DMSO molecules in concentration range 0–50% DMSO and temperature range 30.6 °С – 70°С. DMSO (mol%)
EG EG EG EG DMSO DMSO DMSO DMSO 30,6°С 40,0°С 50,5°С 70,0°С 30,6°С 40,0°С 50,5°С 70,0°С
0 0,44 1,19 2,78 5 6,92 9,28 14,42 28,57 49,03 100
0,120 0,120 0,121 0,128 0,133 0,137 0,149 0,168 0,226 0,296
0,171 0,173 0,173 0,180 0,186 0,193 0,203 0,222 0,287 0,395
0,242 0,242 0,249 0,261 0,270 0,279 0,288 0,317 0,398 0,528
0,428 0,448 0,440 0,453 0,466 0,477 0,496 0,534 0,652 0,808
0,112 0,132 0,137 0,140 0,160 0,172 0,232 0,330 0,815
0,173 0,181 0,198 0,206 0,229 0,294 0,427 0,971
0,268 0,275 0,284 0,296 0,325 0,408 0,558 1179
0,428 0,459 0,477 0,492 0,542 0,661 0,847 1660
operations were carried out in a dry chamber in a stream of dry nitrogen. The samples were thermostated in the spectrometer sensor at a given temperature with an accuracy of ± 1 °C. The error of the selfdiffusion coefficient did not exceed 5%. 3. Results The experimental data of the self-diffusion coefficients of DMSO and EG molecules are presented in Table 2 and in Fig. 1, their calculated
899
Table 3 Activation energies of the self-diffusion process of EG and DMSO at different concentrations DMSO in temperature range 30.6 °С – 70 °С. DMSO (mol%)
Ea, Kcal/mol EG
0 0,44 1,19 2,78 5 6,92 9,28 14,42 28,57 49,03 100
6,68 6,9 6,76 6,65 6,61 6,57 6,36 6,14 5,64 5,25
DMSO
6,31 6,46 6,43 5,98 6,07 5,56 4,95 3,75
activation energies of the self-diffusion processes of DMSO and EG molecules in the temperature range 30 °C – 70 °C are given in Table 3. 4. Discussion For technical reasons, we could not perform measurements at lower temperatures than 30 °C; DMSO has a melting point 18.4 °C. At all temperatures, the self-diffusion coefficients of the DMSO and EG molecules are increasing monotonically with increasing DMSO concentration in the solution. Only at 30 °C, the self-diffusion coefficient of EG molecules in the solution of the lowest studied concentration (0.44 mol% DMSO) does not change its value in comparison with pure EG. The device does not register a smaller concentration. The activation energies of the self-diffusion process are decreasing monotonically. A decrease of the mobility of solvent molecules (EG) at low concentrations of DMSO, accompanying solvophobic solvation [15], was not recorded by this method. The evidence for the existence of solvophobic effects in the EG-DMSO system was shown only in paper [17] on the basis of the concentration dependence of the volume properties - the minimum
Fig. 1. Self-diffusion coefficients (D·10−5, cm2/c) EG and DMSO molecules in concentration range 0–50% DMSO и temperature range 30.6°С – 70 °С.
900
M.N. Rodnikova et al. / Journal of Molecular Liquids 248 (2017) 898–901
Table 4 Comparison of molecular mobility of DMSO, HMPA and EG in individual liquids in temperature range 30 °С – 50 °С. T, °С
D·105, cm2/s
30 40 50
DMSO 0,815 0,971 1179
HMPA 0,344 0,425 0,497
EG 0,120 0,171 0,242
30÷50
Ea, Kcal/mol 3,62
3,86
6,90
effects of tetramethylurea (TMU) are found in aqueous and ethylene glycol solutions of this substance [22]. 5. Conclusions
molar-partial volume of DMSO at very low concentrations ~ 2 mol% DMSO. The hydrophobic part of the DMSO molecule is relatively small. The high heats of mixing DMSO with EG indicate a strong chemical interaction in the system leading to the formation of compounds 1:2 and 1:1 (phase diagram of the EG-DMSO system [18] and quantum chemical calculations [19]). It is interesting to compare the obtained results with the analogous data of the EG-HMPA system obtained by us earlier [3]. In Table 4 there are the data of self-diffusion coefficients in individual liquids. Fig. 2 shows the concentration dependences of the self-diffusion coefficients of EG and DMSO molecules in the EG-DMSO system and of EG and HMPA molecules in the EG-HMPA system at ~40 °C in the concentration range up to 16 mol%. In the EG-DMSO system, we can see monotonous increase of the self-diffusion coefficient of EG and DMSO molecules. We can see the minimum values of self-diffusion coefficients of HMPA and EG at a concentration in the range of ~ 7 mol% of HMPA in the EG-HMPA system. Thus, solvophobic effects are noticeable in the EG-HMPA system, and there are no solvophobic effects in the EG-DMSO system. A greater hydrophobicity/hydrophilicity ratio is confirmed of the HMPA molecule than of the DMSO molecule, which we proposed as a comparative assessment of the hydrophobicity (solvophobicity). Let us recall that the volume and structure of the non-electrolyte molecule play an essential role in the comparison. So when comparing the hydrophobicity of tetrahydrofuran (THF) and dioxane (DO), the ratios of the hydrophobic/hydrophilic parts of the molecule are almost equal: 4 (CH2)/20 = 0.2 for THF and 4 (CH 2)/14.8 = 0.27 for DO, but the composition and the structure of these molecules are completely different. Therefore, solvophobic effects were observed in an ethylene glycol solutions of THF [20], and no solvophobic effects in ethylene glycol solutions of DO [21]. Solvophobic
The system EG-DMSO was studied in the temperature range 30–70 °C using spin-echo approach on protons. A monotonous increase of mobility of EG and DMSO molecules increasing DMSO concentration in solution is observed; solvophobic effects are not detected. Comparison is made with the EG-HMPA system, in which solvophobic effects were recorded. The difference between these systems is explained by the greater hydrophobic component of the HMPA molecule, estimated by the ratio of the number of hydrophobic CH3-groups in the molecule to its Gutman electrondonating ability [4]. The work was carried out within the framework of the state assignment of IGIC RAS in the frame of fundamental scientific research with financial support of the Russian Foundation for Basic Research (Grants 15-03-04007 and 16-03-00897). References [1] D. Banik, N. Kundu, J. Kuchlyan, et al., J. Chem. Phys. (2015)https://doi.org/10.1063/ 1.4906541 (V.142. P.054505 and references in this article). [2] M.N. Rodnikova, Russ. J. Phys. Chem. A 67 (1993) 275. [3] Z.Sh. Idiatullin, I.A. Solonina, M.N. Rodnikova, D.A. Sirotkin, Russ. J. Phys. Chem. A 91 (8) (2017) 1426, https://doi.org/10.7868/S0044453717080131. [4] V. Gutman, “Chemistry of Coordination Compounds in Non-aqueous Solutions” M. Izd-vo “Mir”, 1971. [5] A.K. Soper, A. Luzar, J. Phys. Chem. 100 (1996) 1357, https://doi.org/10.1021/ jp951783r. [6] M.N. Rodnikova, Yu.A. Zakharova, I.A. Solonina, D.A. Sirotkin, Russ. J. Phys. Chem. A 86 (2012) 993. [7] G.I. Egorov, D.M. Makarov, Russ. J. Phys. Chem. A 83 (2009) 805. [8] J.T.W. Lai, F.W. Lau, D. Robb, et al., J. Solut. Chem. 24 (1995) 89. [9] Acros Organics. Catalog of Fine Chemicals. (Vol. 2002–2003). [10] O.Ya. Osipov, V.I. Minkin, A.D. Granovsky, Handbook on Dipole Moments, M.: Publ. Higher School, 1971. [11] J.Y. Gal, C. Moliton-Bouchetout, Bull. Soc. Chim. Fr. (1973) 464. [12] Ch. Wohlfarth, in: M.D. Lechner (Ed.), Landolt-Börnstein-Group IV Physical Chemistry 25: Physical Chemistry, Springer-Verlag, Berlin Heidelberg, 2009https://doi. org/10.1007/978-3-540-75486-2. [13] CRC Handbook of Chem. Phys.74th ed. (1993–1994) [14] Yu.M. Kessler, M.G. Fomicheva, N.M. Alpatova, V.P. Emelin, Russ. J. Eng. Chem. 13 (1972) 517. [15] M.N. Rodnikova, Structural Self-organization in Solutions and at the Interface of Phases(M. Publ. URSS C.151) 2008. [16] V.D. Fedotov, Yu.F. Zuev, V.P. Archipov, Z.Sh. Idiyatullin, Appl. Magn. Reson. 11 (1996) 7.
Fig. 2. Concentration dependences of self-diffusion coefficients of EG and DMSO molecules in system EG - DMSO and EG and HMPA in system EG - HMPA.
M.N. Rodnikova et al. / Journal of Molecular Liquids 248 (2017) 898–901 [17] G.I. Egorov, D.M. Makarov, Russian Chemistry and Chemical Technology, Vol. 54, 2011 65. [18] I.A. Solonina, M.N. Rodnikova, M.R. Kiselev, A.V. Khoroshilov, Russ. J. Phys. Chem. A (2018) (in press). [19] R.A. Vergenz, I. Yazji, C. Whittington, J. Daw, K.T. Tran, J. Am. Chem. Soc. l25 (40) (2003) 12318, https://doi.org/10.1021/ja036516a. [20] M.N. Rodnikova, Yu.A. Zakharova, D.B. Kayumova, I.A. Solonina, Russ. J. Phys. Chem. A 84 (2010) 518.
901
[21] D.B. Kayumova, M.N. Rodnikova, Yu.A. Zakharova, T.M. Valkovskaya, N.V. Kiruta, M.A. Gunina, Abstracts of the report at the 9th Kurnakov meeting on physical and chemical analysis, Perm, Vol. 99, 2010. [22] M.N. Rodniokova, F.M. Samigullin, J. Barthel, D.B. Kaumova, J. Phys. Chem. (Russ.) 78 (N2) (2004) 376.