Adsorption (2011) 17: 561–571 DOI 10.1007/s10450-011-9327-5 Characterization of Supported Ionic Liquid Phase (SILP) materials prepared from different supports Jesus Lemus · Jose Palomar · Miguel A. Gilarranz · Juan J. Rodriguez Received: 15 August 2010 / Accepted: 18 January 2011 / Published online: 1 February 2011 © Springer Science+Business Media, LLC 2011 Abstract Supported ionic liquid phase (SILP) materials are a recent concept where a film of ionic liquid (IL) is immobilized on a solid phase, combining the advan- tages of ILs (non volatility, high solvent capacity, etc.) with those of heterogeneous support materials. In this work, new SILP materials were prepared using a series of supports with different porosity and chemical nature. An imidazolium-based IL, 1-methyl-3-octylimidazolium hexafluorophosphate (OmimPF 6 ), was confined at variable contents (5–60% w/w) in three different activated carbons (ACs), silica (SiO 2 ), alumina (Al 2 O 3 ) and titania (TiO 2 ). For the first time, a systematic characterization of differ- ent SILP systems has been carried out applying a variety of analytical and spectroscopic techniques to provide in- formation of interest on these materials. Elemental analy- sis (EA), adsorption–desorption isotherms of N 2 at 77 K, mercury porosimetry, termogravimetric analysis (TGA), dif- ferential scanning calorimetry (DSC), scanning electronic microscopy (SEM) and energy dispersive X-ray (EDX) were conducted to explore confinement effects. The results demonstrate that EA is a useful tool for quantifying the amount of imidazolium-based IL incorporated on support, independently of the nature of the solid. An excellent corre- lation has been obtained between the percentage of elemen- tal nitrogen and the IL loaded on the support. The combi- nation of nitrogen adsorption–desorption isotherms at 77 K and mercury porosimetry measurements was used to char- acterize the pore structure of both supports and SILP mate- rials. It was found that depending on the available pores in the solid support, the IL tends to fill micropores firstly, then J. Lemus · J. Palomar · M.A. Gilarranz · J.J. Rodriguez ( ) Seccion de Ingenieria Quimica, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid, Spain e-mail: juanjo.rodriguez@uam.es mesopores and lately in macropores. Thermal properties of SILP materials were studied herein by using both TGA and DSC methods, evidencing that the stability of SILP materi- als and the decomposition mechanism are strongly depen- dent on the surface chemistry of the solid support. SEM and EDX provided evidences of external surface coverage by ILs and filling of macropores at high IL load. Keywords Ionic liquids · SILP · Supported ionic liquid phase · Characterization · Activated carbon · Porous structure · Thermal stability 1 Introduction ILs posses an array of properties that make them attractive for academy and industry: extremely low vapor pressure, high thermal and chemical stabilities, non-flammability and high solvent capacity (Welton 1999; Wasserscheid and Wel- ton 2008; Rogers and Seddon 2003). Moreover, the sol- vent properties of the IL are tunable by the choice of the cation/anion combination (Riisager et al. 2003). Because of their unique properties the applications of ILs have been ex- panding in various fields (Rogers and Seddon 2005). Thus, ILs have been extensively examined as an alternative to conventional organic solvents in reaction and separation processes (Rogers and Seddon 2005; Han and Armstrong 2007). There are a number of advantages of ILs in separa- tion and reaction systems, but in many cases there is a need to immobilize them on porous materials (Wasserscheid and Welton 2008). The supported ILs can be spread on the in- ner surface of the porous structure, maintaining large spe- cific surface area and mechanical properties of the support, thus circumventing the problem of mass transport limitation and the need for high amounts of ILs (Zhang et al. 2009a;