Supporting Information

Primary and secondary aqueous two-phase systems composed of

thermo switchable polymers and bio-derived ionic liquids

Cher Pin Song, a Ramakrishnan Nagasundara Ramanan, a,b R. Vijayaraghavan, c Douglas R

MacFarlane, c Eng-Seng Chan, a João A. P. Coutinho, d Luis Fernandez d,e and Chien-Wei

Ooi*a,b

a Chemical Engineering Discipline, School of Engineering, Monash University Malaysia, Jalan

Lagoon Selatan, 47500 Bandar Sunway, Selangor Malaysia.

b Tropical Medicine and Biology Platform, School of Science, Monash University Malaysia,

Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor Malaysia.

c School of Chemistry, Faculty of Science, Monash University, Clayton, VIC 3800, Australia.

d CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro,

3810-193 Aveiro, Portugal.

e Laboratorio de Termodinamica y Fisicoquímica de Fluidos, 35071-Parque Científico-

Tecnologico, Universidad de Las Palmas de Gran Canaria, Canary Islands, Spain

Synthesis procedure and characterization data for [Ch][AA]

Four different types of cholinium aminoate ([Ch][AA]), namely cholinium lysinate ([Ch][Lys],

molecular mass = 249.4 g mol-1), cholinium β-alaninate ([Ch][β-Ala], molecular mass = 192.3

g mol-1), cholinium glycinate ([Ch][Gly], molecular mass = 178.3 g mol-1) and cholinium

serinate ([Ch][Ser], molecular mass = 208.1 g mol-1), were synthesized as per the procedure

described in the literature.1 Typically, [Ch][AA]s were made by mixing aqueous “20 wt%”

choline hydroxide ([Ch][OH]) [note: batch analysis from manufacturer (Sigma Aldrich)

specifies an actual concentration at 20.9 wt% for this batch. The actual concentration of [Ch]

[OH] was confirmed by an aqueous titration with standard 0.1 M HCl solution] with the

corresponding aqueous AA solutions at 1:1 by mole. This was followed by distilling off the

water at 343.15 K under reduced pressure. The final product was dried at 333.15 K for two

days at vacuum. The stoichiometry in the obtained product was confirmed by comparison of

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the pH of a 0.1 M of final product with an aqueous titration curve of the starting materials (i.e.,

0.1 M of [Ch][OH] and 0.1 M of AA solution). Note that the “end-point” in the titration curves

of the AA solution is indistinct and is not directly useful as an indicator of an equimolar

stoichiometry. The [Ch][AA]s were characterized by Electrospray Mass Spectrometry, and

NMR (1H NMR and 13C NMR) Spectroscopy. The water content was analyzed by Karl-Fischer

titration method.

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29

30

31

32

33

34

Cholinium lysinate ([Ch][Lys])

Aqueous solution of L-lysine (5.9 g, 40.1 mmol) was slowly added to 20 wt% aqueous [Ch]

[OH] (23.3 g, 40.1 mmol) and the [Ch][Lys] was made as per the procedure given above.

Electrospray Mass Spectrometry (cone 30 V):

[Ch][Lys], m/z (relative intensity, %): ES+, 104.1 (Me3N+CH2CH2OH, 100); ES-, 145.0

(lysinate, 100)

1H NMR (300 MHz, D2O, TMS): δ = 1.26–1.41 (m, 2H, CH2), 1.43–1.54 (m, 2H, CH2), 1.55–

1.67 (m, 2H, CH2), 2.6–2.64 (t, 2H, CH2), 3.2 (s, 10H, CH3–N, CH–N), 3.48–3.51 (t, 2H, CH2),

4.01–4.06 (m, 2H, CH2)

13C NMR (75 MHz, D2O, TMS): δ = 22.4, 31.2, 40.2, 53.8, 67.3,183.4

Water content (average triplicate in wt%) = 4.8

pH of 0.1 M [Ch][Lys] = 12.1

3

(a)

35

36

37

38

39

40

41

42

43

44

45

46

47

48

0 5 10 15 20 2510

11

12

13

14

Volume of 0.1 M L-lysine used (ml)

pH

Fig. S1 (a) 1H NMR spectra for [Ch][Lys] in D2O; (b) 13C NMR spectra for [Ch][Lys] in D2O;

(c) titration curve for titration of 10 mL of 0.1 M [Ch][OH] with 0.1 M L-lysine in water. The

pH of 0.1 M [Ch][Lys] = 12.1

4

(b)

(c)

49

50

51

52

53

54

55

Cholinium serinate ([Ch][Ser])

Aqueous solution of L-serine (5.0 g, 48 mmol) was slowly added to 20 wt% aqueous [Ch][OH]

(27.8 g, 48 mmol) and the [Ch][Ser] was made as per the procedure given above.

Electrospray Mass Spectrometry (cone 30 V):

[Ch] [Ser], m/z (relative intensity, %): ES+, 104.1 (Me3N+CH2CH2OH, 100); ES-, 104.0

(serinate, 100)

1H NMR (300 MHz, D2O, TMS): δ = 3.18 (s, 9H, CH3–N), 3.36–3.38 (t, 1H, CH–N), 3.48–

3.51 (t, 2H, CH2), 4.01–4.07 (m, 2H, CH2), 3.6–3.78 (m, 2H, CH2)

13C NMR (75 MHz, D2O, TMS): δ = 53.7, 55.5, 57.3, 64.2, 179.5

Water content (average triplicate in wt%) = 2.8

pH of 0.1 M [Ch][Ser] = 10.5

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(a)

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0 5 10 15 20 259

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11

12

13

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Volume of 0.1 M L-serine used (ml)

pH

Fig. S2 (a) 1H NMR spectra for [Ch][Ser] in D2O; (b) 13C NMR spectra for [Ch][Ser] in D2O;

(c) titration curve for titration of 10 mL of 0.1 M [Ch][OH] with 0.1 M L-serine in water. The

pH of 0.1 M [Ch][Ser] = 10.5

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(b)

(c)

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Cholinium glycinate ([Ch][Gly])

Aqueous solution of glycine (4.2 g, 56.1 mmol) was slowly added to 20 wt% aqueous [Ch]

[OH] (32.5 g, 56.1 mmol) and the [Ch][Gly] was made as per the procedure given above.

Electrospray Mass Spectrometry (cone 30 V):

[Ch] [Gly], m/z (relative intensity, %): ES+, 103.6 (Me3N+CH2CH2OH, 100); ES-, 74.2

(glycinate, 100)

1H NMR (300 MHz, D2O, TMS): δ = 3.18 (s, 9H, CH3–N), 3.21 (s, 2H, CH2–N), 3.48–3.52 (m,

2H, CH2), 4.01–4.06 (m, 2H, CH2)

13C NMR (75 MHz, D2O, TMS): δ = 44.1, 53.8, 65.2, 179.7

Water content (average triplicate in wt%) = 5.1

pH of 0.1 M [Ch][Gly] = 11.2

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(a)

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0 5 10 15 20 2510

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Volume of 0.1 M glycine used (ml)

pH

Fig. S3 (a) 1H NMR spectra for [Ch][Gly] in D2O; (b) 13C NMR spectra for [Ch][Gly] in D2O;

(c) titration curve for titration of 10 mL of 0.1 M [Ch][OH] with 0.1 M glycine in water. The

pH of 0.1 M [Ch][Gly] = 11.2

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(c)

(b)

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Cholinium β-alaninate ([Ch][β-Ala])

Aqueous solution of β-alanine (4.6 g, 52 mmol) was slowly added to 20 wt% aqueous [Ch]

[OH] (30.2 g, 52 mmol) and the [Ch] [β-Ala] was made as per the procedure given above.

Electrospray Mass Spectrometry (cone 30 V):

[Ch] [β-Ala], m/z (relative intensity, %): ES+, 104.1 (Me3N+CH2CH2OH, 100); ES-, 87.9 (β-

alaninate, 100)

1H NMR (300 MHz, D2O, TMS): δ = 2.2–2.3 (m, 2H, CH2), 2.7–2.8 (m, 2H, CH2), 3.18 (s, 9H,

CH3–N), 3.48–3.51 (m, 2H, CH2), 4.0–4.05 (m, 2H, CH2)

13C NMR (75 MHz, D2O, TMS): δ = 39.7, 53.8, 55.4, 65.2, 180.7

Water content (average triplicate in wt%) = 4.6

pH of 0.1 M [Ch][β-Ala] = 11.8

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(a)

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Fig. S4 (a) 1H NMR spectra for [Ch][β-Ala] in D2O; (b) 13C NMR spectra for [Ch][β-Ala] in

D2O; (c) titration curve for titration of 10 mL of 0.1 M [Ch][OH] with 0.1 M β-alaninate in

water. The pH of 0.1 M [Ch][β-Ala] = 11.8

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0 5 10 15 20 2510

11

12

13

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Volume of 0.1 M β-alaninate used (ml)

pH(b)

(c)

109

110

111

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114

115

200 250 300 350 4000.0

0.5

1.0

1.5

2.0

2.5

3.0

Wavelength (nm)

Abso

rban

ce (A

bs)

Fig. S5 Wavelength scanning for PPG 400 and [Ch][AA]. 50 wt% PPG 400;

20 wt% [Ch][Lys]; 20 wt% [Ch][Ser]; 20 wt% [Ch][Gly]; 20 wt%

[Ch][β-Ala]

11

277 nm

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117

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120

0 5 10 15 20 250.0

0.5

1.0

1.5

2.0

f(x) = 0.0910709021839216 xR² = 0.999380305002494

Concentration of [Ch][Lys] (wt%)

Absor

bance

(Abs

)

0 5 10 15 20 250.0

0.5

1.0

1.5

2.0

2.5

3.0

f(x) = 0.13335360917451 xR² = 0.997592776624803

Concentration of [Ch][Ser] (wt%)

Absor

bance

(Abs)

0 5 10 15 20 250.0

0.5

1.0

1.5

2.0

2.5

f(x) = 0.115777698690196 xR² = 0.998339163048423

Concentration of [Ch][Gly] (wt%)

Absor

bance

(Abs

)

0 5 10 15 20 250.0

0.5

1.0

1.5

2.0

2.5

f(x) = 0.121052369541176 xR² = 0.996528668090932

Concentration of [Ch][β-Ala] (wt%)

Absor

bance

(Abs)

Fig. S6 Standard curves of [Ch][AA] solutions. The absorbance was measured at 277 nm

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123

0 5 10 15 20 25 30 35 400

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60

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80

90

100

100 w2

100 w1

0 5 10 15 20 250

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60

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100 w2

100 w1

0 5 10 15 20 25 30 350

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60

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80

90

100

100 w2

100 w1

Fig. S7 Plait points for PPG 400 (1) + [Ch][Lys] (2) + water (3) systems. experimental

binodal data; ̶ ̶ ̶ ̶ ̶ ̶ calculated binodal data from Eq. (6); experimental tie-line data;

auxiliary point; plait point; total composition (a) 288.15 K; (b) 298.15 K; (c) 308.15 K

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(c)

(a) (b)

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125

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129

0 5 10 15 20 25 30 35 400

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100

100 w2

100 w1

0 5 10 15 20 25 300

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20

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100 w2

100 w1

0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100 w2

100 w1

Fig. S8 Plait points for PPG 400 (1) + [Ch][Ser] (2) + water (3) systems. experimental

binodal data; ̶ ̶ ̶ ̶ ̶ ̶ calculated binodal data from Eq. (6); experimental tie-line data;

auxiliary point; plait point; total composition (a) 288.15 K; (b) 298.15 K; (c) 308.15 K

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(c)

(a) (b)

130

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135

0 5 10 15 20 25 30 35 400

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100

100 w2

100 w1

0 5 10 15 20 25 300

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100 w2

100 w1

0 5 10 15 20 250

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50

60

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80

90

100

100 w2

100 w1

Fig. S9 Plait points for PPG 400 (1) + [Ch][Gly] (2) + water (3) systems. experimental

binodal data; ̶ ̶ ̶ ̶ ̶ ̶ calculated binodal data from Eq. (6); experimental tie-line data;

auxiliary point; plait point; total composition (a) 288.15 K; (b) 298.15 K; (c) 308.15 K

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(c)

(a) (b)

136

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0 5 10 15 20 25 30 35 40 45 500

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100 w2

100 w1

0 5 10 15 20 25 300

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100 w2

100 w1

0 5 10 15 20 25 30 350

10

20

30

40

50

60

70

80

100 w2

100 w1

Fig. S10 Plait points for PPG 400 (1) + [Ch][β-Ala] (2) + water (3) systems. experimental

binodal data; ̶ ̶ ̶ ̶ ̶ ̶ calculated binodal data from Eq. (6); experimental tie-line data;

auxiliary point; plait point; total composition (a) 288.15 K; (b) 298.15 K; (c) 308.15 K

16

(c)

(a) (b)

141

142

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145

146

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.20

1

2

3

4

5(a)

0.0 0.5 1.0 1.5 2.0 2.5 3.00

1

2

3

4

5(b)

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.50

1

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(c)

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.50

1

2

3

4

5

(d)

Fig. S11 Setschenow-type plots for tie-line data of PPG 400 (1) + [Ch][AA] (2) + water (3)

systems at different temperatures. (a) [Ch][Lys]; (b) [Ch][Ser]; (c) [Ch][Gly]; (d) [Ch][β-Ala];

288.15 K; 298.15 K; 308.15 K

17

ln (m¿¿1t ¿¿m1b¿)¿¿¿

(m¿¿2b−m2t )¿/mol kg-1

ln (m¿¿1t ¿¿m1b¿)¿¿¿

ln (m¿¿1t ¿¿m1b¿)¿¿¿ln (m¿¿1t ¿¿m1

b¿)¿¿¿

(m¿¿2b−m2t )¿/mol kg-1

(m¿¿2b−m2t )¿/mol kg-1

(m¿¿2b−m2t )¿/mol kg-1

147

148

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0 10 20 30 40 500

10

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100 w2

100 w1

(a)

0 10 20 30 40 50

0

10

20

30

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50

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80

90

100

100 w2

100 w1

(b)

0 10 20 30 40 500

10

20

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50

60

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80

90

100 w2

100 w1

(c)

0 10 20 30 40 50

0

10

20

30

40

50

60

70

80

100 w2

100 w1

(d)

Fig. S12 Tie-line data of PPG 400 (1) + [Ch][AA] (2) + water (3) systems at 288.15 K (black),

298.15 K (red) and 308.15 K (blue). (a) [Ch][Lys]; (b) [Ch][Ser]; (c) [Ch][Gly]; (d) [Ch][β-

Ala]; and ── represent the experimental tie-line data; and ----- represent the calculated

tie-line data using Setschenow-type equation

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156

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0 10 20 30 40 500

10

20

30

40

50

60

70

80

90

100

100 w2

100 w1

0 5 10 15 20 25 30 35 40 450

10

20

30

40

50

60

70

80

90

100

100 w2

100 w1

0 5 10 15 20 25 30 35 40 450

10

20

30

40

50

60

70

80

90

100 w2

100 w1

0 5 10 15 20 25 30 35 40 45 500

10

20

30

40

50

60

70

80

100 w2

100 w1

Fig. S13 Tie-line data of PPG 400 (1) + [Ch][AA] (2) + water (3) systems at 288.15 K (black),

298.15 K (red) and 308.15 K (blue). (a) [Ch][Lys]; (b) [Ch][Ser]; (c) [Ch][Gly]; (d) [Ch][β-

Ala]; and ── represent the experimental tie-line data; and ----- represent the calculated

tie-line data using e-NRTL model

19

(b)

(c)

(a)

(d)

163

164

165

166

167

168

169

Table S1 Absorbance values (Abs) for the mixture of PPG 400 and [Ch][AA] at 277 nm

Concentration of [Ch][AA] (wt%)

Concentration of PPG 400 (wt%) sda

0 8 10 15[Ch][Lys]

10 0.97 0.95 0.96 0.95 0.00615 1.42 1.42 1.40 n.d.b 0.01220 1.80 1.77 n.d.b n.d.b 0.021

[Ch][Ser]10 1.45 1.45 1.45 1.44 0.00515 2.06 2.05 2.06 n.d.b 0.00620 2.50 2.50 n.d.b n.d.b 0.000

[Ch][Gly]10 1.18 1.18 1.19 1.17 0.00815 1.82 1.82 1.83 n.d.b 0.00620 2.25 2.23 n.d.b n.d.b 0.014

[Ch][β-Ala]10 1.33 1.32 1.31 1.33 0.01015 1.93 1.91 1.92 n.d.b 0.01020 2.28 2.26 n.d.b n.d.b 0.014

a sd =¿¿, where |¿| represents the absorbance value, z is the concentration of PPG 400 [where z = (8, 10 and 15) wt%] and n is the number of absorbance values measured

b n.d. represents data not determined. The total composition of these systems was above the critical concentrations for the formation of two-phase solution.

20

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171172

173174

175

176

Table S2 Experimental binodal data for PPG 400 (1) + [Ch][AA] (2) + water (3) systems at T = (288.15a, 298.15a,b and 308.15a) K and pressure p = 101.32 kPa

T = 288.15 K T = 298.15 Kb T = 308.15 K100 w1 100 w2 100 w1 100 w2 100 w1 100 w2

PPG 400 + [Ch][Lys] + water17.3 19.2 10.3 17.2 11.5 19.219.4 17.5 13.0 13.6 14.2 14.921.8 15.8 15.5 11.8 15.8 12.024.6 13.2 18.8 10.0 18.3 9.7829.4 11.8 20.4 9.32 19.8 9.0333.6 10.6 23.6 8.26 23.4 8.2041.8 7.43 24.7 7.68 24.7 7.6745.1 6.31 28.1 6.74 28.8 6.9047.0 5.98 29.4 6.42 30.4 6.6453.7 4.48 34.0 5.66 33.3 5.5554.8 4.22 35.2 5.42 34.6 5.3256.4 4.03 36.4 5.19 35.5 5.0858.4 3.89 39.3 4.71 37.7 4.5360.8 3.58 45.1 3.72 41.5 3.4262.0 3.44 49.7 2.76 47.0 2.61

PPG 400 + [Ch][Ser] + water15.4 17.1 10.6 17.7 10.6 17.717.2 15.5 13.3 13.9 12.8 13.519.5 14.2 15.9 12.1 14.9 11.322.8 12.3 19.1 10.2 17.0 9.0527.8 11.0 20.6 9.43 18.3 8.3531.4 9.87 23.7 8.31 20.8 7.2942.5 7.55 25.2 7.83 22.2 6.8946.3 6.48 28.2 6.76 25.3 6.0648.5 6.18 29.5 6.44 27.1 5.9058.8 4.90 34.2 5.69 31.7 5.2860.7 4.67 35.3 5.42 33.6 5.1763.4 4.52 36.3 5.18 35.0 5.0166.4 4.43 38.9 4.66 39.4 4.7371.4 4.20 46.1 3.79 47.9 3.9574.9 4.16 53.7 2.99 60.9 3.58

PPG 400 + [Ch][Gly] + water15.8 17.6 10.0 16.7 7.86 13.117.5 15.8 11.8 12.4 9.90 10.420.2 14.7 13.9 10.6 11.9 9.0323.6 12.7 17.6 9.40 14.7 7.8227.0 10.8 19.3 8.82 16.3 7.4730.5 9.58 22.8 7.97 19.6 6.8638.7 6.88 24.2 7.51 20.9 6.5142.0 5.87 26.9 6.46 23.8 5.7044.5 5.66 28.3 6.18 25.6 5.4857.4 4.78 32.5 5.41 29.5 4.9258.9 4.53 33.8 5.21 30.6 4.7060.3 4.31 35.0 5.00 31.6 4.5263.2 4.22 37.1 4.45 33.9 4.0765.6 3.86 42.5 3.50 40.1 3.30

21

177178

67.7 3.76 50.1 2.78 45.7 2.51

PPG 400 + [Ch][β-Ala] + water17.2 19.2 9.13 16.7 10.3 17.219.4 17.5 12.3 12.9 13.1 13.821.7 15.8 15.4 11.7 14.9 11.325.4 13.7 18.7 9.98 17.5 9.3529.1 11.7 20.7 9.44 18.5 8.4732.3 10.2 23.6 8.26 20.9 7.3240.9 7.27 24.6 7.65 22.6 7.0445.1 6.31 28.0 6.71 25.4 6.0947.0 5.98 29.0 6.33 26.9 5.8652.8 4.40 33.3 5.55 30.5 5.0854.3 4.18 35.1 5.40 31.6 4.8655.9 3.99 36.0 5.14 33.1 4.7258.3 3.89 38.9 4.67 35.3 4.2361.5 3.62 39.2 4.61 41.5 3.4263.0 3.50 49.9 2.77 46.4 2.73

a Standard uncertainty of temperature, u(T) = 1 K. Expanded uncertainty: for PPG 400 + [Ch][Lys] + water system, Uc are Uc(PPG 400) = Uc([Ch][Lys]) = 0.0018 (95% level of confidence); for PPG 400 + [Ch][Ser] + water system, Uc(PPG 400) = Uc([Ch][Ser]) = 0.0027 (95% level of confidence); for PPG 400 + [Ch][Gly] + water system, Uc(PPG 400) = Uc([Ch][Gly]) = 0.0022 (95% level of confidence); for PPG 400 + [Ch][β-Ala] + water system, Uc(PPG 400) = Uc([Ch][β-Ala]) = 0.0033 (95% level of confidence)

b Data taken from literature1

22

179180181182183184185

Table S3 Values of parameters of Eq. (3) for PPG 400 + [Ch][AA] + water systems at T = (288.15, 298.15 and 308.15) K

T (K) f g R2 sd a

PPG 400 + [Ch][Lys] + water288.15 65.61 0.607 0.982 0.785298.15 -2.905 2.612 0.971 0.825308.15 35.90 1.497 0.968 1.075

PPG 400 + [Ch][Ser] + water288.15 65.27 0.600 0.993 0.306298.15 -6.330 2.218 0.981 0.498308.15 41.40 1.563 0.966 1.344

PPG 400 + [Ch][Gly] + water288.15 51.52 0.960 0.991 0.374298.15 -16.88 2.602 0.973 1.109308.15 34.69 1.975 0.971 1.230

PPG 400 + [Ch][β-Ala] + water288.15 40.25 0.796 0.989 0.489298.15 -29.95 3.354 0.978 0.875308.15 29.06 1.078 0.962 1.234

a sd =¿¿, where w1 represents the concentration of PPG 400 (wt%) and n is the number of tie-line data

23

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Reference

(1) Song, C. P.; Ramanan, R. N.; Vijayaraghavan, R.; MacFarlane, D. R.; Chan, E.-S., Ooi, C.-

W. Green, aqueous two-phase systems based on cholinium aminoate ionic liquids with

tunable hydrophobicity and charge density. ACS Sus. Chem. Eng., 2015, 3, 3291-3298.

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