Screening of Supported Ionic Liquid Phase (SILP) catalysts for the very low temperature water–gas-shift reaction

Werner, Sebastian; Szesni, Normen; Bittermann, Agnes; Schneider, M.; Härter, Peter; Haumann, Marco; Wasserscheid, Peter

doi:10.1016/j.apcata.2010.01.019

Cited by 72 publications

(53 citation statements)

References 41 publications

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“…Shortly later, Riisager et al published the first successful example of continuous gas-phase SILP catalysis [63]. During the last years, many technically relevant examples of SILP catalysis have been published, including examples of hydroformylation [64,65], hydrogenation [66,67], enantioselective hydrogenation [68,69], water gas shift reaction [70,71], alkene metathesis [72,73], hydroamination [74] and carbonylation of methanol [75]. Additional valuable information about SILP catalysis has been collected in reviews by Riisager et al [76,77], Gu and Li [78], van Doorslaer et al [79], and Virtanen et al [80].…”

Section: Supported Ionic Liquid Phase (Silp) Catalysismentioning

confidence: 99%

Ionic Liquids in Catalysis

2014

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Ionic liquids (ILs), salts with melting points below 100°C, represent a fascinating class of liquid materials typically characterized by an extremely low vapor pressure. Besides their application as new solvents or as electrolytes for electrochemical purposes, there are two important concepts of using ILs in catalysis: Liquid-liquid biphasic catalysis and IL thin film catalysis. Liquid-liquid biphasic catalysis enables either a very efficient manner to apply catalytic ILs, e.g. in Friedel-Crafts reactions, or to apply ionic transition metal catalyst solutions. In both cases, phase separation after reaction allows an easy separation of reaction products and catalyst re-use. One problem of liquidliquid biphasic catalysis is mass transfer limitation. If the chemical reaction is much faster than the liquid-liquid mass transfer the latter limits the overall reaction rate. This problem is overcome in IL thin film catalysis where diffusion pathways and thus the characteristic time of diffusion are short. Here, Supported Ionic Liquid Phase (SILP) and Solid Catalyst with Ionic Liquid Layer (SCILL) are the two most important concepts. In both, a high surface area solid substrate is covered with a thin IL film, which contains either a homogeneously dissolved transition metal complex for SILP, or which modifies catalytically active surface sites at the support for SCILL. In each concept, interface phenomena play a very important role: These may concern the interface of an IL phase with an organic phase in the case of liquidliquid biphasic catalysis. For IL thin film catalysis, the interfaces of the IL with the gas phase and with catalytic nanoparticles and/or support materials are of critical importance. It has recently been demonstrated that these interfaces and also the bulk of ILs can be investigated in great detail using surface science studies, which greatly contributed to the fundamental understanding of the catalytic properties of ILs and supported IL materials. Exemplary results concerning the IL/vacuum or IL/gas interface, the solubility and surface enrichment of dissolved metal complexes, the IL/support interface and the in situ monitoring of chemical reactions in ILs are presented.

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Section: Supported Ionic Liquid Phase (Silp) Catalysismentioning

confidence: 99%

Ionic Liquids in Catalysis

2014

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“…The latest developments in SILP systems can be divided in two great blocks as catalysis (Riisager et al 2003(Riisager et al , 2005b(Riisager et al , 2006a(Riisager et al , 2006bVirtanen et al 2007Virtanen et al , 2009aVirtanen et al , 2009bRuta et al 2008) and separation processes (Zhang et al 2009a;Vioux et al 2010;Sun et al 2009;Fontanals et al 2009;Fang et al 2010;Kohler et al 2010;Werner et al 2010;Joni et al 2010). In catalytic processes, a variety of reactions have been studied where SILP proved to be more active and selective than common systems.…”

Section: Introductionmentioning

confidence: 98%

Characterization of Supported Ionic Liquid Phase (SILP) materials prepared from different supports

et al. 2011

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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 advantages 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 different SILP systems has been carried out applying a variety of analytical and spectroscopic techniques to provide information of interest on these materials. Elemental analysis (EA), adsorption-desorption isotherms of N 2 at 77 K, mercury porosimetry, termogravimetric analysis (TGA), differential 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 correlation has been obtained between the percentage of elemental nitrogen and the IL loaded on the support. The combination of nitrogen adsorption-desorption isotherms at 77 K and mercury porosimetry measurements was used to characterize the pore structure of both supports and SILP materials. It was found that depending on the available pores in the solid support, the IL tends to fill micropores firstly, then 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 materials and the decomposition mechanism are strongly dependent 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.

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“…The WGS studies with different ionic liquid loading on the SILP material were conducted in a continuous gas phase fixedbed reactor previously described in detail [23][24][25]. The activity of the catalysts was determined directly from online lGC mea-surements (Varian CP4900 with 10 m MS5A and 10 m PPQ columns).…”

Section: Introductionmentioning

confidence: 99%

Solid‐State NMR Investigations of Supported Ionic Liquid Phase Water‐Gas Shift Catalysts: Ionic Liquid Film Distribution vs. Catalyst Performance

Haumann¹,

Schönweiz

Breitzke

et al. 2012

Chem Eng & Technol

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The ionic liquid film distribution in supported ionic liquid phase (SILP) catalysts has been studied by solid-state NMR.[EMIM][NTf 2 ] was immobilized onto silica gel 100 support with loadings between 0 and 40 vol.-%. The 1 H NMR signals indicated an exchange process between the support's surface silanol groups and the protons of the ionic liquid. At ionic liquid loadings below 10 vol.-%, islands of ionic liquids seemed to form, whereas at higher loadings complete coverage of the support was achieved. The NMR-based film model was confirmed by gas phase water-gas shift experiments using known SILP catalysts with different ionic liquid loadings. At high ionic liquid loading, the activity of the catalyst decreased due to pore blocking. The NMR technique provided easy and reliable data for film formation and distribution and allows for optimization of SILP catalysts in the future.

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Screening of Supported Ionic Liquid Phase (SILP) catalysts for the very low temperature water–gas-shift reaction

Cited by 72 publications

References 41 publications

Ionic Liquids in Catalysis

Ionic Liquids in Catalysis

Characterization of Supported Ionic Liquid Phase (SILP) materials prepared from different supports

Solid‐State NMR Investigations of Supported Ionic Liquid Phase Water‐Gas Shift Catalysts: Ionic Liquid Film Distribution vs. Catalyst Performance

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