271315 The Influences of Grafting Solvent and Surface-Linking Groups On the Structure-Function Relationships of Surface Organometallic Catalysts

Thursday, November 1, 2012: 12:30 PM
319 (Convention Center )
Eric G. Moschetta, Chemical Engineering, Pennsylvania State University, University Park, PA and Robert M. Rioux, Chemical Engineering, The Pennsylvania State University, University Park, PA

The Influences of Grafting Solvent and Surface-Linking Groups on the Structure-Function Relationships of Surface Organometallic Catalysts

Eric G. Moschetta and Robert M. Rioux*

Department of Chemical Engineering

The Pennsylvania State University, University Park, PA 16802

*rioux@engr.psu.edu

Surface organometallic catalysts are synthesized to mimic their homogeneous counterparts in the hopes that they behave with similar activity and selectivity while adding the benefit of facile separation and recyclability. The surface-linking group can impart different effects due to the nature of the linking atom (e.g. P, N) and the flexibility or rigidity of the tethering backbone. A more subtle influence is present in the form of the grafting solvent used as the medium to transfer the organometallic species to the surface-modified support, which can alter the structure of the organometallic species, thereby altering the nature of the active site.

We present studies of the hydrothiolation of thiophenol and phenylacetylene as a model reaction using Wilkinson's catalyst (RhCl(PPh3)3) supported on functionalized SBA-15 using various surface-linking groups and grafting solvents to compare catalytic activities and selectivities. We also present results for homogeneously catalyzed reactions using Wilkinson's catalyst in each grafting solvent under otherwise identical hydrothiolation conditions as the heterogeneous reactions. Additionally, we characterize the supported catalysts using techniques such as solid-state NMR. Finally, we compare the structures of the synthesized catalysts and use the obtained kinetic data, both homogeneous and heterogeneous, to draw conclusions regarding the role of each grafting solvent and the different ligand tethers on the resulting activity and selectivity of each catalyst.


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See more of this Session: Fundamentals of Supported Catalysis I
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