David A. Durkee
	Graduate Student Researcher B.S. Chemical Engineering, 2001 University of Illinois at Urbana Co-Advised by: Alexis T. Bell Research Interest: Polymer Bound Catalysts for Chiral Synthesis Block Copolymers for Nanostructured Catalysts Research | Resume | Publications
David A. Durkee 201G Gilman Hall UC Berkeley Dept. of Chemical Engineering Berkeley, CA 94720 USA Lab Phone 510-643-5037 Email Me!

Research Description:

Chiral drugs continue to be a force in the global pharmaceutical market. With worldwide sales as high as $100 billion in 2000, and the market continually growing, the desire for heterogeneous synthesis route grows.

Most therapeutic molecules are a single enantiomer, and where possible, the commercial form is also single enantiomer. Racemics are sometimes used, but after racemic Thalidomide caused 10,000 birth defects, chiral synthetic routes were desired to avoid similar catastrophes.

Chiral synthesis is most often achieved with a homogeneous catalyst. However, heterogeneity is desired to ease separation. Polymers are good candidates for this task. Most chiral synthesis reactions occur at modest temperatures (for resolution of one enantiomer), which are well below the thermal decomposition temperature of polymers. Also, the products, reactants, and catalysts are all very expensive, thus allowing for a more expensive recovery vehicle, such as polymers, to be used. Finally, pharmaceuticals must be very high purity, which means that catalyst must be removed and not incorporated into the final product, as is done with other chemicals.

Our strategy for the immobilization of catalysts on polymeric material uses block copolymers, and has several advantages. Block copolymers are known to form several distinct micro-phases. These can be used to template a nanostructured catalyst material in which the support, active sites, and pores are all locally uniform. This method allows for very precise control over the catalyst environment. The local catalyst concentration will be much higher than that of it homogenous analogues, which may lead to elevated reaction rates. Also, unlike other polymer bound catalysts, the material will be porous, with the interior of the pores lined with catalytic sites. Consequently, the surface area of the support is fully utilized, while diffusion limitations are minimized.

The new approach may prove to be more effective than current methods for immobilization of chiral catalysts, and give a unique arena for the study of catalyst-support interactions. To our knowledge, nanostructured catalysts of this type have not been synthesized or studied.

This project represents a collaboration between the Balsara group that specializes in the synthesis and self-assembly of block copolymers, and the Bell group that specializes in catalyst design and evaluation.

 
  Publications:

D.A. Durkee, H.B. Eitouni, E.D. Gomez, M.W. Ellsworth, A.T. Bell, and N.P. Balsara, “Catalysts from Self-Assembled Organometallic Block Copolymers”, Advanced Materials, 2005, 17, 2003.

B.A. Garetz, M.C. Newstein, J.D. Wilbur, A.J. Patel, D.A. Durkee, R.A. Segalman, J.A. Liddle, and N.P. Balsara, “Grain Structure in Block Copolymer Thin Films Studied by Guided Wave Depolarized Light Scattering”, Macromolecules, 2005, 38, 4282.