evidence for the interactions occurring between ionic liquids and...

Evidence for the Interactions Occurring between

Ionic Liquids and Tetraethylene Glycol in Binary

Mixtures and Aqueous Biphasic Systems

Luciana I. N. Tomé‡, Jorge F. B. Pereira‡,†, Robin D. Rogers†, Mara G. Freire‡, José R. B.

Gomes‡ and João A. P. Coutinho

‡*

‡CICECO, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro, Portugal

† Center for Green Manufacturing and Department of Chemistry, The University of Alabama,

Tuscaloosa, AL, 35487, USA

This Supporting Information contains: the densities for binary mixtures of water and TEG calculated from

the MD simulations (Table S1); full set of electrostatic charges for the ILs and TEG model (Tables S2 to S6);

compositions (wt%) of the mixtures at which the MD calculations and the 1H NMR experiments were

performed (Table S7); compositions of the biphasic region of the [C4mim]Cl/PEG/water phase diagram at

which the additional MD simulations were performed (Table S8); comparison of the experimental and

calculated densities for binary mixtures of water and TEG (Figure S1); compositions of the experimental

phase diagrams of the ABS composed of PEG 1500 and [C4mim]Cl at which the 1H NMR experiments and

the MD simulations were performed (Figure S2); 1H NMR chemical shifts deviations between PEG-200 and

[C4mim]Cl (Figures S3 and S4); radial distribution functions between the anion and cation of [C2mim]Cl and

the hydrogen and carbon atoms of TEG (Figures S5 and S6); snapshot from a simulation of

([C4mim]Cl+TEG) (Figure S7); radial distribution functions between the anions and selected atoms of the

cations of [C1mim]Cl/[C4mim]Cl/[C6mim]Cl and different molecular regions of TEG for the binary systems

(Figures S8 to S13); comparison of the radial distribution functions for the interactions of selected groups of

TEG with the anions (Figure S14) and with selected atoms of the cations (Figures S15 to S18) for the binary

systems and with water (Figure S19) for the different ternary systems; radial distribution functions between

the anion and cation of [C4mim]Cl and the hydrogen and carbon atoms of TEG for (TEG + [C4mim]Cl +

water) ternary mixtures (Figures S20 and S21); radial distribution functions between the anions and selected

atoms of the cations of [C1mim]Cl/[C2mim]Cl//[C6mim]Cl and different molecular regions of TEG for the

ternary systems (Figures S22 to S27), and the references complete author list.

Table S1. Densities (ρ) for binary mixtures of water (1) + TEG (2) at T = 298.15 K calculated

from the MD simulations.

xwater ρ / (kg·m-3)

0.00 1124.17 0.09 1125.21 0.20 1124.63 0.50 1124.72 0.60 1123.98 0.70 1122.14 0.80 1115.41 0.90 1093.16 1.00 999.35

Table S2. Atomic charges used in the MD simulations for [C1mim]Cl. Atom numbering

corresponds to the adjacent diagram.

Atom numbering Electrostatic

Charges / e

1 N 0.179

2 C -0.140

3 C -0.140

4 N 0.179

5 C -0.117

6 C -0.230

7 H 0.141

8 C -0.230

9 H 0.219

10 H 0.219

11 H 0.215

12 H 0.141

13 H 0.141

14 H 0.141

15 H 0.141

16 H 0.141



Atom numbering Electrostatic Charges

/ e 1N 0.065

2 C -0.142

3 C -0.135

4 N 0.191

5 C -0.109

6 C -0.224

7 H 0.138

8 C 0.118

9 H 0.221

10 H 0.206

11 H 0.225

12 H 0.052

13 H 0.052

14 H 0.138

15 H 0.138

16 C -0.120

17 H 0.062

18 H 0.062

19 H 0.062




Charges / e

1 C -0.118

2 N 0.161

3 C -0.117

4 C -0.203

5 N 0.214

6 C -0.223

7 C -0.229

8 C 0.162

9 C 0.169

10 C -0.267

11 H 0.205

12 H 0.237

13 H 0.226

14 H 0.139

15 H 0.139

16 H 0.139

17 H 0.112

18 H 0.112

19 H -0.022

20 H -0.022

21 H -0.018

22 H -0.018

23 H 0.074

24 H 0.074

25 H 0.074




Charges / e

1 C -0.124

2 C -0.175

3 N 0.133

4 C -0.081

5 N 0.164

6 C -0.131

7 C 0.228

8 C -0.039

9 C -0.035

10 C -0.256

11 H 0.092

12 H 0.092

13 H 0.009

14 H 0.009

15 H 0.218

16 H 0.147

17 C 0.212

18 H 0.232

19 H -0.040

20 H 0.205

21 H -0.040

22 H 0.147

23 H 0.010

24 H 0.010

25 H 0.147

26 C -0.235

27 H -0.035

28 H -0.035

29 H 0.057

30 H 0.057

31 H 0.057

Table S6. Atomic charges used in the MD simulations for TEG. Atom numbering corresponds to

the adjacent diagram.


Charges / e

1 O -0.568

2 C 0.284

3 H 0.000

4 H 0.000

5 C 0.284

6 H 0.000

7 H 0.000

8 C 0.284

9 H 0.000

10 H 0.000

11 O -0.568

12 C 0.284

13 H 0.000

14 H 0.000

15 C 0.284

16 H 0.000

17 H 0.000

18 O -0.568

19 C 0.284

20 H 0.000

21 H 0.000

22 C 0.216

23 H 0.014

24 H 0.014

25 O -0.700

26 H 0.456

27 C 0.216

28 H 0.014

29 H 0.014

30 O -0.700

31 H 0.456

Table S7. Composition (xwt%) of the mixtures at which the MD calculations and the 1H NMR

experiments were performed.

MD [C4mim]Cl TEG water 40.3 59.7 0.0 32.4 46.5 21.1 1H NMR [C4mim]Cl PEG-200 water

1st set 17.30 0.00 74.33

17.01 1.94 73.07 16.56 4.29 71.13 16.34 6.03 70.22 15.60 10.18 67.01 13.92 20.16 59.79

2nd set 0.00 19.97 74.33

1.67 20.40 75.93 3.33 19.34 71.97 4.78 19.92 74.11 9.05 18.26 67.93 17.10 16.78 62.43

3rd set 17.37 82.63 0.00

17.14 81.53 1.84 16.77 79.73 3.54 16.40 77.97 5.59 15.77 75.01 9.25

Table S8. Compositions of the biphasic region of the [C4mim]Cl/PEG/water phase diagram [ref.

40] at which the additional MD simulations were performed.

Number of ion pairs/molecules considered in the MD simulations

Mole fraction

[C4mim]Cl TEG water [C4mim]Cl PEG1500 water Binary system 160 40 - 0.80 0.20 -

Ternary system 160 40 40 0.67 0.17 0.17 160 40 80 0.57 0.14 0.29 160 40 190 0.41 0.10 0.49

Figure S1. Experimental (ref. 80) and calculated (this work) densities (ρ) for binary mixtures of

water (1) + TEG (2) at T = 298.15 K.

0.98

1.00

1.02

1.04

1.06

1.08

1.10

1.12

1.14

0.00 0.20 0.40 0.60 0.80 1.00 1.20

ρρ ρρ(g/cm

3)

x1

experimental (ref 80)

MD simulations (this work)

Figure S2. Experimental phase diagrams for the ABS composed of PEG 1500 and [C4mim]Cl at

323.15 K (red squares) and 333.15 K (black dots) [ref. 40]. The blue triangles represent the

compositions at which the MD simulations were performed and the green triangles represent the

compositions at which the 1H NMR experiments were performed.

Figure S3. 1H NMR chemical shifts deviations between PEG-200 and [C4mim]Cl in deuterated

aqueous solutions and that of pure [C4mim]Cl (1.0 mol·kg-1) in heavy water as a function of

PEG-200 molality.

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0 0.2 0.4 0.6 0.8 1

∆δH/ pp

m CPEG200 / (mol.kg-1)

H2

H5

H4

HB1

Htm

HB2

HB3

Htb

-

0.0033.035.037.039.041.0

CD2O / (mol.Kg-1)

Figure S4. 1H NMR chemical shifts deviations between PEG-200 and [C4mim]Cl in deuterated

aqueous solutions and that of pure PEG-200 (1.0 mol·kg-1) in heavy water as a function of

[C4mim]Cl molality.

0.00

0.01

0.02

0.03

0.04

0 0.2 0.4 0.6 0.8 1

∆δH/ p

pm

C[C4mim]Cl / (mol.kg-1)

Hc

Hb

Ha

0.0033.035.037.039.041.0

CD2O / (mol.Kg-1)

Figure S5. Radial distribution functions between the anion of [C2mim]Cl and the hydrogen

atoms of TEG.

(a)

(b)

(c)

(d)

Figure S6. Radial distribution functions between selected atoms of the cation of [C2mim]Cl and

the hydrogen and carbon atoms of TEG.

Figure S7. Snapshot from a simulation of ([C4mim]Cl+TEG) showing the preferential

conformations adopted by the TEG molecules and the distances (Å) between selected atoms.

Red, white and green spheres represent oxygen atoms, hydrogen atoms and chloride ions,

respectively.

Figure S8. Radial distribution functions between the anion of [C1mim]Cl and different

molecular regions of TEG.

(a)

(b)

(c)


different molecular regions of TEG.

(a)

(b)

(c)

(d)

(a)

(b)

(c)

(d)



Figure S14. Comparison of the RDFs for the interactions of TEG protons and the anion of

[C1mim]Cl, [C2mim]Cl, [C4mim]Cl and [C6mim]Cl.

Figure S15. Comparison of the RDFs for the interactions of the oxygen atom of the hydroxyl

group of TEG and the H4 atom of the imidazolium ring of the cation of [C1mim]Cl, [C2mim]Cl,

[C4mim]Cl and [C6mim]Cl.

Figure S16. Comparison of the RDFs for the interactions of the O1 atom of TEG and the H2

atom of the imidazolium ring of the cation of [C1mim]Cl, [C2mim]Cl, [C4mim]Cl and

[C6mim]Cl.

Figure S17. Comparison of the RDFs for the interactions of the oxygen atom of the hydroxyl

group of TEG and the terminal carbon atom of the cation of [C1mim]Cl, [C2mim]Cl, [C4mim]Cl

and [C6mim]Cl.

Figure S18. Comparison of the RDFs for the interactions of the ether oxygens of TEG and the

terminal carbon atom of the cation of [C1mim]Cl, [C2mim]Cl, [C4mim]Cl and [C6mim]Cl.

Figure S19. Comparison of the RDFs for the interaction of the hydrogen atoms of water with the

O1 and O(OH) atoms of TEG, for the systems (TEG + IL + water).

Figure S20. Radial distribution functions between the anion of [C4mim]Cl and the hydrogen and

carbon atoms of TEG for (TEG + [C4mim]Cl + water) ternary mixtures.

(a)

(b)

(c)

(d)

(e)

(f)

(g)


different regions of TEG, for (TEG + [C4mim]Cl + water) ternary mixtures.


molecular regions of TEG, for (TEG + [C6mim]Cl + water) ternary mixtures.

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)


different molecular regions of TEG, for (TEG + [C6mim]Cl + water) ternary mixtures.


molecular regions of TEG, for (TEG + [C2mim]Cl +water) ternary mixtures.

(a)

(b)

(c)

(d)




molecular regions of TEG, for (TEG + [C1mim]Cl + water) ternary mixtures.

(a)

(b)



References: Complete author list

(84) Frisch, M.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Scalmani, G.; Barone, V.; Mennucci, B.; Petersson, G. A.; Nakatsuji, H.; Caricato, M.; Li, X.; Hratchian, H. P.; Izmaylov, A. F.; Bloino, J.; Zheng, G.; Sonnenberg, J. L.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Vreven, T.; Montgomery Jr., J. A.; Peralta, J. E.; Ogliaro, F.; Bearpark, M.; Heyd, J. J.; Brothers, E.; Kudin, K. N.; Staroverov, V. N.; Kobayashi, R.; Normand, J.; Raghavachari, K.; Rendell, A.; Burant, J. C.; Iyengar, S. S.; Tomasi, J.; Cossi, M.; Rega, N.; Millam, J. M.; Klene, M.; Knox, J. E.; Cross, J. B.; Bakken, V.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Martin, R. L.; Morokuma, K.; Zakrzewski, V. G.; Voth, G. A.; Salvador, P.; Bannenberg, J. J.; Dapprich, S.; Daniels, A. D.; Farkas, O.; Foresman, J. B.; Ortiz, J. V.; Cioslowski, J.; Fox, D. J. Gaussian 09, Revision A.02; Gaussian, Inc.: Wallingford CT, 2009.

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