Associate Professor of Chemistry
EMSL Project ID
30202
Abstract
The reaction between an oxygen atom and an olefin to form an epoxide remains an important research area in industrial and synthetic chemistry, because epoxides are the main ingredients in epoxy resins, paints, surfactants and intermediates in various organic syntheses. The main goal of this proposed research is to discover new catalysts to accomplish epoxidations using hydrogen peroxide. H¬2O2 can oxide organic compounds with relatively high atom efficiency and water is one of the by-products. It is our intention to utilize large diameter mesoporous silica nanoparticle materials containing complexes capable of oxidation in the hope of discovering new catalytic systems. Compared to MCM-type silicas, SBA-15 type silicas, which can be obtained in the presence of nonionic triblock surfactants, have attracted great interest due to their larger pores, thicker pore walls and higher hydrothermal stability. The pore size can be tuned up to 30 nm by using a swelling agent such as 1,3,5-trimethylbenzene. Very little work has been done to support the molybdenum or tungsten complex on the surface or interior of SBA-15 type silicas. We hope to produce such compounds in this research and it is hoped that they may prove useful as catalysis for oxidation with hydrogen peroxide and that some may function as chiral catalysts as substrates may have an orientation preference going through the channels. The characterization of these materials by TEM is essential for their complete characterization and this is the area we hope to conduct in collaboration with Dr. Theva Thevuthasan at the EMSL. The research will accomplish the preparation of active oxidation heterogenous catalysts that will accomplish the oxidation of olefins with minimum use of toxic materials. It will be interesting if we see differences in the activity of the catalysts embedded inside the nanotubules. We will demonstrate that complexes can be supported inside of the pore cavities, as these are large-sized pores and should be able to accommodate the catalyst and substrate. There is also the possibility of chiral catalytic ability and this can be envisioned to occur via two mechanisms. First, it is possible to place substituents containing hydrophilic or hydrophobic substituents within the initial pore cavity. This may preferentially orient the substrate molecule leading to stereospecific oxygen addition. Secondly, such a preferential orientation may occur within the pore cavity due to the hindered location of the catalyst itself (bound up within the pore) as the active site may only be accessible with one particular orientation of the substrate. This may have applications towards the oxidation of "fine chemicals."
Project Details
Project type
Large-Scale EMSL Research
Start Date
2008-08-21
End Date
2009-08-23
Status
Closed
Released Data Link
Team
Principal Investigator