16523-89-0Relevant articles and documents
Synthesis, immobilization, MAS and HR-MAS NMR of a new chelate phosphine linker system, and catalysis by rhodium adducts thereof
Guenther,Reibenspies,Bluemel
experimental part, p. 443 - 460 (2011/04/16)
A new class of tridentate phosphine ligands with the general formula [MeP{(CH2)xPPh2}3]+I - (x=4, 7, 11) and [MeP(CH2PPh2) 3]+OTf-, has been synthesized and fully characterized. The linkers have been immobilized on silica with their phosphonium moieties via electrostatic interactions, and their mobility and leaching has been studied by solid-state HR-MAS (high-resolution magic angle spinning) NMR in various solvents. Immobilized Wilkinson-type rhodium complexes have been obtained by ligand exchange with the surface-bound linkers. The activities and lifetimes of the catalysts have been tested with respect to the hydrogenation of 1-dodecene. The rhodium catalyst precursor bound by the immobilized linker [MeP{(CH2)7PPh2} 3]+I- led to material with the highest activity and lifetime, and it could be recycled for 30atimes in a batchwise manner. The other catalysts show shorter lifetimes. For all catalysts the formation of rhodium nanoparticles with a narrow size distribution around 4anm has been proven.
Preparation of organohalosilanes
-
, (2008/06/13)
In an industrial process for preparing organohalosilanes by reacting metallic silicon particles with an organohalide in the presence of a copper catalyst, a contact mass composed of the metallic silicon and the catalyst further contains an effective amount of a phosphine chalcogenide compound. The invention drastically increases the silane formation rate and the utilization of silicon without lowering the selectivity of useful silane.
