title: Ruthenium carbenes supported on mesoporous silicas as highly active and selective hybrid catalysts for olefin metathesis reactions under continuous flow.
abstract: In the search for a highly active and selective heterogenized metathesis catalyst, we systematically varied the pore geometry and size of various silica-based mesoporous (i.e., MCM-41, MCM-48, and SBA-15) and microporous (ZSM-5 and MWW) versus macroporous materials (D11-10 and Aerosil 200), besides other process parameters (temperature, dilution, and mean residence time). The activity and, especially, selectivity of such "linker-free" supports for ruthenium metathesis catalysts were evaluated in the cyclodimerization of cis-cyclooctene to form 1,9-cyclohexadecadiene, a valuable intermediate in the flavor and fragrance industry. The optimized material showed not only exceptionally high selectivity to the valuable product, but also turned out to be a truly heterogeneous catalyst with superior activity relative to the unsupported homogeneous complex.
authors.affiliation: CaRLa-Catalysis Research Laboratory, Im Neuenheimer Feld 584, 69120 Heidelberg, Germany.
authors.forename: Miriam
authors.initials: M
authors.lastname: Bru
authors.forename: Richard
authors.initials: R
authors.lastname: Dehn
authors.forename: J Henrique
authors.initials: JH
authors.lastname: Teles
authors.forename: Stephan
authors.initials: S
authors.lastname: Deuerlein
authors.forename: Manuel
authors.initials: M
authors.lastname: Danz
authors.forename: Imke B
authors.initials: IB
authors.lastname: Müller
authors.forename: Michael
authors.initials: M
authors.lastname: Limbach
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry*
chemical_list: D000475:Alkenes; C030011:carbene; D012428:Ruthenium; D008697:Methane
keywords: cyclooligomerization; macrocycles; mesoporous materials; metathesis; ruthenium; supported catalysts