Lehrstuhl fur Chemische Reaktionstechnik

Erlangen, Germany

Lehrstuhl fur Chemische Reaktionstechnik

Erlangen, Germany
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Walter S.,Lehrstuhl fur Chemische Reaktionstechnik | Haumann M.,Lehrstuhl fur Chemische Reaktionstechnik | Wasserscheid P.,Lehrstuhl fur Chemische Reaktionstechnik | Hahn H.,Evonik Industries | And 2 more authors.
AIChE Journal | Year: 2015

A novel gas-phase process has been developed that allows direct two-step conversion of butane into pentanals with high activity and selectivity. The process consists of alkane dehydrogenation over a heterogeneous Cr/Al2O3 catalyst followed by direct gas-phase hydroformylation using advanced supported ionic liquid phase (SILP) catalysis. The latter step uses rhodium complexes modified with the diphosphite ligands biphephos (BP) and benzopinacol to convert the butane/butene mixture from the dehydrogenation step efficiently into aldehydes. The use of the BP ligand results in improved yields of linear pentanal because SILP systems with this ligand are active for both isomerization and hydroformylation. © 2014 American Institute of Chemical Engineers.

Schonweiz A.,Lehrstuhl fur Chemische Reaktionstechnik | Debuschewitz J.,Lehrstuhl fur Chemische Reaktionstechnik | Walter S.,Lehrstuhl fur Chemische Reaktionstechnik | Wolfel R.,Lehrstuhl fur Chemische Reaktionstechnik | And 6 more authors.
ChemCatChem | Year: 2013

Ligand-modified Rh complexes were physically adsorbed on the surface of porous silica. The resulting materials were subjected to the continuous gas-phase hydroformylation of C2 and C4 alkenes. The ligands used for catalyst modification were bidentate phosphorus ligands known from the literature, namely, sulfoxantphos (1) and a benzopinacol-based bulky diphosphite 2. The tested catalyst materials were active and, in particular, selective as in comparable homogeneous liquid-phase experiments. Long-term stability experiments over 1000h on stream showed minor deactivation. A significant increase in the catalyst mass after the reaction was detected by weighing and thermogravimetric analysis. By using headspace-GC-MS, the mass increase could be attributed to high-boiling compounds, which are formed insitu during the catalytic reaction itself and accumulate inside the pores of the support. Evidence is given that the initially physisorbed catalyst complexes dissolve in the high-boiling aldol side-products, which are suitable solvents for the active catalyst species and provide a liquid-phase environment held by capillary forces on the support. It's all in the pores! Ligand-modified Rh complexes are physically adsorbed onto the surface of porous silica and the resulting solid materials are subjected to continuous gas-phase hydroformylation of C2 and C4 alkenes. The catalyst materials were surprisingly active and, in particular, exhibited similar selectivity to liquid-phase reactions. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Haumann M.,Chemical Reaction Engineering | Jakuttis M.,Lehrstuhl fur Chemische Reaktionstechnik | Franke R.,EvonikOxeno GmbH | Schonweiz A.,Lehrstuhl fur Chemische Reaktionstechnik | Wasserscheid P.,Lehrstuhl fur Chemische Reaktionstechnik
ChemCatChem | Year: 2011

The concept of supported ionic liquid phase (SILP) catalysis has been established in recent years by our group and others. Its application in continuous catalytic gas-phase processes provides a very attractive way to bridge the gap between homogeneous and heterogeneous catalysis. In this contribution, we extend SILP hydroformylation catalysis to reactions with a highly diluted, technical C4 feed containing 1.5% 1-butene, 28.5% 2-butenes, and 70% of inert n-butane. To obtain the desired product, n-pentanal, the Rh-biphephos catalyst system was immobilized in the SILP system to allow for consecutive isomerization/hydroformylation activity. The resulting SILP catalyst material converted up to 81% of the reactive butenes, with a residence time of 155s in the reactor. An n-pentanal selectivity greater than 92% was realized for more than 500h time-on-stream in the continuous gas-phase reaction. Post-reaction NMR studies revealed no significant loss of the phosphite ligand through ligand oxidation during the reaction. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Werner S.,Lehrstuhl fur Chemische Reaktionstechnik | Werner S.,University of California at Berkeley | Szesni N.,Clariant | Kaiser M.,Clariant | And 2 more authors.
Chemical Engineering and Technology | Year: 2012

Supported ionic liquid phase (SILP) catalysts consist of a homogeneous catalyst that is dissolved in an ionic liquid and dispersed on a porous support material. This immobilization technique yields solid catalysts that can be applied in continuous gas phase processes. Recently, several successful applications have been presented that could possibly lead to a commercialization of this promising class of novel materials. The state-of-the-art preparation method uses an incipient wetness-type impregnation of the support material by a solution of catalyst, ionic liquid, and a helper solvent, followed by subsequent removal of the helper solvent in vacuo. Typically, this removal is carried out in a rotary evaporator, thus being limited in batch size. Similarly, the so-called supported catalysts with ionic liquid layer (SCILL) consist of an ionic liquid layer on top of a traditional heterogeneous catalyst, which can be prepared in a similar way. In this work, a novel preparation method for SILP catalysts is presented that is scalable for larger batches, as required for industrial use. Different types of support materials such as powders, spheres, agglomerates, and extrudates were successfully impregnated by the novel fluidized-bed impregnation method and the distribution of the ionic liquid and catalyst was analyzed by scanning electron microscopy with energy-dispersive X-ray spectroscopy measurements. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Distaso M.,Lehrstuhl fur Feststoff und Grenzflachenverfahrenstechnik | Klupp Taylor R.N.,Lehrstuhl fur Feststoff und Grenzflachenverfahrenstechnik | Taccardi N.,Lehrstuhl fur Chemische Reaktionstechnik | Wasserscheid P.,Lehrstuhl fur Chemische Reaktionstechnik | Peukert W.,Lehrstuhl fur Feststoff und Grenzflachenverfahrenstechnik
Chemistry - A European Journal | Year: 2011

Polymers and coordinating solvents have been shown to serve as templating agents to assist the precipitation of ZnO nanoparticles and address their morphology. In this work we show for the first time that a difference in the coordination strength between the polymer (poly-N-vinylpyrrolidone (PVP)) and the two ZnII precursor salts (nitrate and acetate) is able to promote or suppress the formation of mesocrystalline structures and even more importantly to tune their three-dimensional organization. On the basis of FTIR and 13C NMR spectroscopic studies, we propose that not only the polymer (PVP) but also the solvent (DMF) play a key role as directing agents. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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