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Solid‐State NMR Investigations of Supported Ionic Liquid Phase Water‐Gas Shift Catalysts: Ionic Liquid Film Distribution vs. Catalyst Performance
Author(s) -
Haumann M.,
Schönweiz A.,
Breitzke H.,
Buntkowsky G.,
Werner S.,
Szesni N.
Publication year - 2012
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.201200025
Subject(s) - ionic liquid , silanol , catalysis , chemistry , phase (matter) , ionic bonding , chemical engineering , analytical chemistry (journal) , inorganic chemistry , ion , chromatography , organic chemistry , engineering
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.