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Ligand‐Modified Rhodium Catalysts on Porous Silica in the Continuous Gas‐Phase Hydroformylation of Short‐Chain Alkenes–Catalytic Reaction in Liquid‐Supported Aldol Products
Author(s) -
Schönweiz Andreas,
Debuschewitz Jonas,
Walter Simon,
Wölfel René,
Hahn Hanna,
Dyballa Katrin M.,
Franke Robert,
Haumann Marco,
Wasserscheid Peter
Publication year - 2013
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201300305
Subject(s) - hydroformylation , catalysis , chemistry , rhodium , heterogeneous catalysis , ligand (biochemistry) , aldol condensation , denticity , aldol reaction , alkene , organic chemistry , chemical engineering , inorganic chemistry , biochemistry , receptor , crystal structure , engineering
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 C 2 and C 4 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 1000 h 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 in situ 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.