L. Keith Woo’s hunt for green catalysts has led him to experiment with iron porphyrins. Here he’s holding a model of an iron porphyrin compound in his Iowa State Univ. research lab. Credit: Bob Elbert. |
L. Keith Woo is searching for cleaner, greener chemical reactions.
Woo, an Iowa State Univ. professor of chemistry and an associate of the Ames
Laboratory, has studied catalysts and the chemical reactions they affect for
more than 25 years. And these days, his focus is on green catalysis.
That, he said, is the search for catalysts that lead to more efficient chemical
reactions. That could mean they promote reactions at lower pressures and
temperatures. Or it could mean they promote reactions that create less waste.
Or it could mean finding safer, cleaner alternatives to toxic or hazardous
conditions.
“We’re trying to design, discover, and optimize materials that will
produce chemical reactions in a way that the energy barrier is lowered,”
Woo said. “We’re doing fundamental, basic catalytic work.”
And much of that work is inspired by biology.
In one project, Woo and his research group are studying how iron porphyrins
can be used for various catalytic applications. Iron porphyrins are the active
sites in a variety of the enzymes that create reactions and processes within a
cell. Most of the iron porphyrin reactions involve oxidation and electron
transfer reactions.
Because the iron porphyrins of biology have evolved into highly specialized
catalysts, Woo and his research group are studying how they can be used
synthetically with the goal of developing catalysts that influence a broader
range of reactions.
“We’ve found porphyrins are capable of doing many reactions—often as
well, or better, or cheaper than other catalysts,” Woo said.
Another project is using combinatorial techniques to accelerate the
development, production, and optimization of catalysts. Woo and his research
group are using molecular biology to screen a massive library of DNA molecules
for catalyst identification and development. The goal is to create
water-soluble catalysts for organic reactions.
“Combinatorial approaches such as these have been applied to drug
design, but their use in transition metal catalyst development is in its infancy,”
Woo wrote in a summary of the project.
A third project is looking for catalysts that allow greener production of
lactams, which are compounds used in the production of solvents, nylons, and
other polymers. Commercial lactam production uses harsh reagents and
conditions, such as sulfuric acid and high temperatures, and also creates
significant wastes.
Woo, in collaboration with Robert Angelici, a Distinguished Professor
Emeritus of Chemistry, has found a gold-based catalyst that eliminates the need
for the acid and high pressure and also eliminates the wastes. The Iowa State
Research Foundation Inc. is seeking a patent on the technology.
And, in a fourth project, Woo is working to understand the chemistry behind
the chemical reactions that create bio-oil from the fast pyrolysis of biomass.
Fast pyrolysis quickly heats biomass in the absence of oxygen to produce a
liquid bio-oil that can be used to manufacture fuels and chemicals.
Woo’s projects are supported by
grants from the National Science Foundation, the U.S. Department of Energy,
Iowa State’s Institute for Physical Research and Technology, Iowa State’s Bioeconomy
Institute, and the National Science Foundation Engineering Research Center for
Biorenewable Chemicals based at Iowa State.
