Characterization of Surface Supported Organometallic Olefin Polymerization Catalysts by High Field Solid-State Multi-Nuclear Magnetic Resonance.
EMSL Project ID
34302
Abstract
Supported early transition metal metallocenes have found increasing use as heterogeneous olefin polymerization catalysts in industry. The heterogeneous disordered nature of these catalysts makes them difficult to characterize with standard organometallic chemistry techniques (e.g. solution NMR and single crystal X-ray diffraction). We propose to characterize silica supported metallocene complexes, which serve as models of industrially relevant heterogeneous catalysts, with 91Zr and 35Cl solid-state NMR. This will enable the direct characterization of the metallocene structure on silica surfaces and provide much insight into the chemical species that are present on the surface and involved in catalysis. The dilute chlorine and zirconium contents of the supported systems is expected to lead to great reductions in the signal to noise of NMR experiments on these systems. This can be rectified by the application of high magnetic fields and cooling of samples to liquid helium temperatures. Both of these capabilities are uniquely found at EMSL. The goals outlined in this proposal will enable future studies of these commercially employed catalysts which will allow for interactions between the Lewis acid co-catalysts, the metallocene catalyst and the surface support to be effectively probed. This will allow for the rational design and improvement of a broad range of heterogeneous catalysts. This objective falls under the category of “Science of Interfacial Phenomena�, which is one of the four key mission statements of the EMSL in that it will promote the “atomic- and molecular-level understanding and control of the dynamic, reactive, and transport properties of interfaces� and aid in the development of “a new generation of selective, efficient, and stable catalysts�.
Project Details
Project type
Limited Scope
Start Date
2009-04-22
End Date
2009-06-22
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members