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Para-hydrogen induced polarization in homogeneous phase-an example of how ionic liquids affect homogenization and thus activation of catalysts

Gutmann, T. and Sellin, M. and Breitzke, H. and Stark, A. and Buntkowsky, G. (2009):
Para-hydrogen induced polarization in homogeneous phase-an example of how ionic liquids affect homogenization and thus activation of catalysts.
In: Physical Chemistry Chemical Physics, pp. 9170-9175, 11, (40), [Online-Edition: http://apps.webofknowledge.com/full_record.do?product=WOS&se...],
[Article]

Abstract

Para-hydrogen induced polarization (PHIP) is observed in an organic solvent-free homogeneous catalyst/substrate system using ionic liquids. The hydrogenation reactions are performed employing a Rh-catalyst/ionic liquid system without further organic solvents. The PHIP phenomenon is demonstrated for the ethyl acrylate system. Small amounts of ionic liquids (ILs) containing weakly coordinating anions such as Tf(2)N(-) act as homogenizing cosolvents for the catalyst in ethyl acrylate, leading to a dramatic activation of the catalytic process and a high PHIP signal enhancement. The achieved enhancement depends strongly on the viscosity of the ethyl acrylate/IL mixture. Furthermore, by deliberate choice of the IL constituents it was possible to design a model system exhibiting both sufficient catalyst solubility and biphasic liquid-liquid behavior. This shows that in ionic liquids PHIP enhancements followed by a fast quantitative removal of the para-hydrogenated product from the catalyst phase is in principle possible. The possible PHIP enhancement factors will depend strongly on the design of a suitable hydrogenation reactor.

Item Type: Article
Erschienen: 2009
Creators: Gutmann, T. and Sellin, M. and Breitzke, H. and Stark, A. and Buntkowsky, G.
Title: Para-hydrogen induced polarization in homogeneous phase-an example of how ionic liquids affect homogenization and thus activation of catalysts
Language: English
Abstract:

Para-hydrogen induced polarization (PHIP) is observed in an organic solvent-free homogeneous catalyst/substrate system using ionic liquids. The hydrogenation reactions are performed employing a Rh-catalyst/ionic liquid system without further organic solvents. The PHIP phenomenon is demonstrated for the ethyl acrylate system. Small amounts of ionic liquids (ILs) containing weakly coordinating anions such as Tf(2)N(-) act as homogenizing cosolvents for the catalyst in ethyl acrylate, leading to a dramatic activation of the catalytic process and a high PHIP signal enhancement. The achieved enhancement depends strongly on the viscosity of the ethyl acrylate/IL mixture. Furthermore, by deliberate choice of the IL constituents it was possible to design a model system exhibiting both sufficient catalyst solubility and biphasic liquid-liquid behavior. This shows that in ionic liquids PHIP enhancements followed by a fast quantitative removal of the para-hydrogenated product from the catalyst phase is in principle possible. The possible PHIP enhancement factors will depend strongly on the design of a suitable hydrogenation reactor.

Journal or Publication Title: Physical Chemistry Chemical Physics
Volume: 11
Number: 40
Uncontrolled Keywords: parahydrogen-induced polarization situ phip-nmr stereoselective hydrogenation heterogeneous hydrogenation complexes rhodium c-13 hyperpolarization hydroformylation solvents
Divisions: 07 Department of Chemistry
07 Department of Chemistry > Physical Chemistry
Date Deposited: 27 Oct 2014 20:42
Official URL: http://apps.webofknowledge.com/full_record.do?product=WOS&se...
Additional Information:

505MW Times Cited:15 Cited References Count:49

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