The Distillation and Volatility of Ionic Liquids Martyn

The Distillation and Volatility of Ionic Liquids Martyn J. Earle, Jose M. S. S. Esperanca, Manuela A. Gilea, Jose N. Canongia Lopes, Luis P. N. Rebelo, Joseph W. Magee, Kenneth R. Seddon & Jason A. Widegren Nature 2006, 439, 831 -834. 1

1 -ethyl-3 -methylimidazolium chloride • [C 2 mim]Cl - Al. Cl 3 system with a greater than 2: 1 excess of Al. Cl 3, a detectable vapour pressure of Al 2 Cl 6 was observed above 191 o. C. • [C 2 mim]Cl 2 190 o. C in vacuum decompose (transalkylation): 1 -methylimidazole, 1 -ethylimidazole, chloromethane, chloroethane, ethene and hydrogen chloride recondense: [C 1 mim]Cl - [C 2 eim]Cl Dymek, C. J. Jr, Hussey, C. L. , Wilkes, J. S. & Øye, H. A. in Joint (Sixth) International Symposium on Molten Salts (eds Mamantov, G. et al. ) 93–-104 (The Electrochemical Society, Pennington, New Jersey, 1987). Øye, H. A. & Wahnsiedler, W. E. in The Fourth International Symposium on Molten Salts (eds Blander, M. , Newman, D. S. , Saboungi, M. L. , Mamantov, G. & Johnson, K. ) 58–-73 (The Electrochemical Society, Pennington, New Jersey, 1984). Jeapes, A. J. et al. Process for recycling ionic liquids. World Patent WO 01/15175 (2001). 2

Yoshizawa, M. , Xu, W. & Angell, C. A. J. Am. Chem. Soc. 2003, 125, 15411–-15419. Kreher, U. P. , Rosamilia, A. E. , Raston, C. L. , Scott, J. L. & Strauss, C. R. Selfassociated, “distillable” ionic media. Molecules, 2004, 9, 387–-393. 3

Apparatus 1. Kugelrohr apparatus 2. Sublimation apparatus 4

[NTf 2]- is bis{(trifluoromethyl)-sulphonyl}amide, also known as bistriflamide, [N(SO 2 CF 3)2]- 5

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cholinium tetraalkylammonium tetraalkylphosphonium [Cx y z. N(C 2 H 4 OH)]+ [NCw x y z]+ [PCw x y z ]+ 7

cholinium tetraalkylammonium tetraalkylphosphonium [Cx y z. N(C 2 H 4 OH)]+ [NCw x y z]+ [PCw x y z ]+ ˇ 8

• Ionic liquids with other anions (for example, halides, sulphates, or carboxylates) decomposed on distillation. • The principal mechanism of decomposition was by dealkylation or transalkylation of the cation. • This is aided by a nucleophilic anion. 9

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No feasible mechanism to transfer a proton to the anion R = H , CH 3 14