SUPPORTING INFORMATION

Interesting Viscosity Changes in the Aqueous Urea-Ionic Liquid System: Effect of Alkyl

Chain Length Attached to the Cationic Ring of an Ionic Liquid

Raju Nanda1, Gitanjali Rai1, Anil Kumar*,1

Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi

Bhabha Road, Pune 411008, India; Tel: +912025902278; E-mail: a.kumar@ncl.res.in

1H NMR spectra of precursors:

CH3-(CH2)7-Br (Bromooctane)

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1H NMR Spectra of CH3-(CH2)5-Br (Bromohexane)

1H NMR Spectra of CH3-(CH2)3-Br (Bromobutane)

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1H NMR Spectra of CH3C3H3N2 (1-Methylimidazole)

1H NMR spectra

[C4mim][BF4]

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[C6mim][BF4]

[C8mim][BF4]

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[C4mim]Br

[C6mim]Br

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[C8mim]Br

Mass spectra of ILs:

[C4mim]Br

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[C6mim]Br

[C8mim]Br

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[C4mim][BF4]

[C6mim][BF4]

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[C8mim][BF4]

CHNS analysis:

Compound Calculated Observed

% C % H % N % C % H % N

[C4mim]Br 43.85 6.9 12.78 43.01 8.09 11.52

[C6mim]Br 48.59 7.75 11.33 47.63 8.76 10.05

[C8mim]Br 52.32 8.42 10.18 51.96 9.53 9.04

[C4mim][BF4] 42.48 6.69 12.39 42.09 7.50 11.04

[C6mim][BF4] 47.23 7.54 11.03 46.99 7.75 9.62

[C8mim][BF4] 51.04 8.22 9.93 50.80 8.32 8.56

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DSC-thermogram of [C4mim][BF4]

DSC-thermogram of [C4mim][BF4] showing a glass transition temperature at around -85.75 0C, which is in agreement with the available literature data (-85 0C)1.

References:

[1] Fredlake, C.P., Crosthwaite, J.M., Hert, D.G., Aki, S.N.V.K., Brennecke, J.F.:

Thermophysical properties of imidazolium-based ionic liquids. J. Chem. Eng. Data 49, 954-964

(2004)

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