Anchoring rhodium(I) on benzoylthiourea-functionalized silica xerogels. Production of recyclable hydroformylation catalysts and the crystal structure of the model compound

Article abstract of DOI:10.1016/0022-328X(94)00009-2

The benzoylthiourea-functionalized silica xerogels, 4.5Si)2*SiO3/2(CH2)3NHC(S)NHC(O)Ph (XGbztu) and SiO3/2(CH2)3NHC(S)NHC(O)Ph (XGbztu^*) have been prepared from (EtO)3Si(CH2)3NHC(S)NHC(O)Ph by the sol-gel process.They are able to bind rhodium(I) species giving the composite materials Rh/XGbztu and Rh/XGbztu^*, which are very active insoluble and recoverable catalysts for the hydroformylation of styrene.The anchored species undergo major changes during the catalytic cycles, particularly in the Rh/XGbztu system, whose iso/normal selectivity ratio gradually increased in the first five runs.Furthermore, CH3(CH2)2NHC(S)NHC(O)Ph (HBztu) has been studied as a model of the surface binding function.The structure of , which represents a suitable molecular model for the anchored complexes, has been determined by X-ray diffraction. Keywords: Rhodium; Xerogel; Crystal structure; Hydroformylation; ESCA; Supported catalyst