ACIDIC IONIC LIQUIDS

REFERENCES ACIDIC IONIC LIQUIDS

1-(4-sulfobutyl)-3-methylimidazolium trifluoromethanesulfonate, 98% ImSF1705c [(CH2)4SO3HMlm][CF3SO3]

1-(4-sulfobutyl)-3-methylimidazolium hydrogen sulfate, 98% ImSF1213c [(CH2)4SO3HMlm][HSO4] 1-(4-sulfobutyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 98% ImSF1808c [(CH2)4SO3HMlm][N(CF3SO2)2]

Experimental aspect :

 Hydrophilic  Liquid at room temperature  Brønsted acids  Stable with water and oxygen  Non-corrosive  Easily recyclable

Solubility :

SOLVENT MISCIBILITY

Water Miscible

Hexane immiscible

Ester immiscible

Applications :

These ionic liquids are used as acid catalysts in the following reactions : Esterification, Oxidation, Alkylation, Beckmann Rearrangement, Cyclotrimerisation… Esterification of ethanol by acetic acid1: Catalyzed by a Brønsted acidic ionic liquid

CH3COOC2H5 + OH 2 Ethyl acetate H SO 2 4 Conversion = 60.3% Selectivity = 98.2%

CH 3COOH + C 2H5OH 60°C, 4 h Acetic acid Ethanol

[(CH2)H4SO3HMIm] [HSO4]

CH3COOC2H5 + OH 2 Ethyl acetate Conversion = 92.8% Selectivity = 100%

The 1-(4-sulfobutyl)-3-methylimidazoliumhydrogensulfate is a more effective catalyst than a conventional catalyst (sulphuric acid H2SO4). The ester formed is extracted by a simple separation and the acidic ionic liquid may then be recycled without any loss of activity (at the 5th recycling, Conversion=88.5% and Selectivity=100%).

Cyclotrimerization of aldehydes2: Catalyzed by an acidic ionic liquid with no addition of any organic solvent

[(CH2)4SO3HMIm] [CF3SO3] O O 3 O 25°C, 1 h O

2, 4, 6-triisopropyl-1, 3, 5-trioxane Isobutyraldehyde Conversion = 93% Selectivity = 100% The Isobutyraldehyde (60 mol) is catalyzed by the 1-(4-sulfobutyl)-3-methylimidazolium trifluoromethanesulfonate (1 mol) in only one hour at room temperature. The product from the reaction is isolated by liquid-liquid extraction with hexane ant the acidic ionic liquid is easily recycled without any loss of activity (at the 5th recycling, Conversion=93% and Selectivity=100%).

1 Jianzhou Gui, Xiaohui Cong, Dan Liu, Xiaotong Zhang, Zhide Hu b, Zhaolin Sun, Catalysis Communications, 5, 473–477, (2004)

2 Jianzhou Gui, Dan Liu, Xiaomei Chen, Xiaotong Zhang, Lijuan Song, and Zhaolin Sun, React.Kinet.Catal.Lett., Vol. 90, No. 1,35−43 (2007)