My project involves elucidating the mechanisms of activation and olefin metathesis for supported rhenium complexes such as methyl trioxorhenium (MTO) and perrhenate. Investigation of theses mechanisms is accomplished through both experimental techniques including EXAFS and solid state NMR, as well as computational methods using the CNSi and Peters’ Group computing clusters. Metathesis has already found wide application in the chemical industry, including the production of propene, specialty polymers, and other chemical feedstocks, as well as for converting dwindling petroleum supplies into more useful hydrocarbon stocks. Although olefin metathesis with homogeneous transition metal complexes as catalysts is considered well-understood, the potentially more useful heterogeneous catalysts remain poorly defined. For example, supported perrhenate catalysts activate spontaneously in the presence of an olefin substrate, but this activation is more efficient in the presence of a promoter such as tetramethyltin; however, the nature of these activation processes is not apparent, nor is the nature of the activated site(s). It is this lack of understanding of catalyst activation which motivates my interest in this project. Elucidation of the activation mechanisms will provide the insight necessary to control the formation of the active sites, and would represent a large step towards the industrial viability of these catalysts. In addition, understanding their deactivation mechanisms is also crucial to improving catalyst lifetime. Accomplishing both would open the door to using olefin metathesis to create a wide variety of important commodity and specialty building blocks from renewable resources, such as soybean oil.

Research sponsored by:

Department of Energy