Melting Point Depression Effect with CO2 in High Melting Temperature Cellulose Dissolving Ionic Liquid

JOANA M. LOPES; FRANCISCO A. SÁNCHEZ; S. BELÉN RODRÍGUEZ REARTES; M. DOLORES BERMEJO; ÁNGEL MARTÍN; M. JOSÉ COCERO ALONSO

Alicante

Congreso; X Iberoamerican Conference on Phase Equilibria and Fluid Properties for Process Design; 2015

Universidad de Alicante

Ionic liquids (ILs) are substances composed entirely of ions that generally are fluid around or below 100˚C . The unique physicochemical properties of ILs such as low vapour pressure and high solvation ability to dissolve various organic and inorganic substances allows their use as green solvents in organic synthesis. One of the most promising application of ionic liquids is cellulose processing. Some IL that dissolve cellulose are very viscous and poses high melting points. To solve this problem, it is know that mixing IL with molecular solvents its viscosity and melting point can be decreased [1]. This is also true when using CO2 as a co-solvent, that has advantages of been also a green solvent and easily separated from ionic liquid by depreessurization. It is known that IL can high amounts of CO2 at moderate pressures and most IL are not soluble in CO2. [2]Ionic liquids based on quaternary ammonium present melting point depressions higher than 100K under 15 MPa of CO2 [3]. Imidazolium and pyridinium cations showed a much lower depression in the range of 20K in the same conditions [4].In this work, the melting temperatures of five different ionic liquids (ILs) able to dissolve cellulose were measured in contact with CO2 using a high-pressure visual cell, up to 10 MPa, using the method of the first melting point. The ionic liquids studied  are  1-butyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium, chloride, 1-(2-hydroxyethyl)-3-methyl-imidazolium chloride and dihydrogen phosphate. The datas were modelled with the GC EoS developed by Skjold Jøorgensen. To do so parameters for the methyl imidazolium chloride group were adjusted using data available in literature.[5] References[1] K.R. Seddon, A. Stark, M.J. Torres, Pure Appl. Chem. 72 (2000) 2275?2287[2] L.A. Blanchard, D. Hancu, E.J. Beckman, J.F. Brennecke, Nature 399 (6731) (1999) 28-29[3] A.M. Scurto, W. Leitner, Chem. Comm. (2006) 3681?3683[4] S.G. Kazarian, N. Sakellarios, C.M. Gordon, Chem. Comm. (2002) 1314-1315[5] S. Jang , D.W. Cho, T. Im, H. Kim, Fluid Phase Equilib. 299 (2010) 216?221