ChBE News
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Josie Giles, School of Chemical & Biomolecular Engineering
Contact Josie Giles josie.giles@chbe.gatech.edu
404-385-2299
Focus on Chemical & Biomolecular Engineering Research
Catalysis, Reaction Kinetics & Reaction Engineering
Atlanta (July 16, 2008) — Chemical reactions occur in a variety of different systems and are essential to most technological areas. Research in the field of catalysis, reaction kinetics, and reaction engineering plays an important role in the development and improvement of numerous applications, including the network of reactions during combustion, the chain reactions that form polymers, the multiple steps in the synthesis of complex pharmaceutical molecules, and the specialized reactions of proteins and metabolism. Catalysts influence the rate of a reaction. Chemical and biomolecular engineers study catalysts with the goals of improving the reaction conditions, emphasizing a desired product, or reducing waste. They are researched to develop methods for increasing production, improving the reaction conditions, and emphasizing a desired product. Chemical engineers design catalysts that are highly effective and stable and then they develop methods to manufacture them. Current topics under investigation in the School include:
• Kinetics and mechanisms of reactions in solution
• Reactions and catalysis in supercritical and gas-expanded fluids
• Phase transfer catalysis
• Tunable fluids for asymmetric catalysis
• Dispersed-phase polymerization
• Homogeneous catalyst immobilization
• Ziegler-Natta and metallocene-mediated olefin polymerization
• Zeolite catalysts
• Catalysis and biocatalysis for pharmaceutical and fine chemical production
• Deactivation mechanisms of protein-based catalysts
• Engineering metal-mediated catalytic reactions in the presence of sulfur
• Catalysis and reaction engineering for clean-up of paper-making waste
The profiles on this page highlight catalysts, reactors, and reaction processes research under investigation by Drs. Agrawal, Chen, and Jones.
PRADEEP AGRAWAL
Dr. Agrawal’s research interests are in the area of heterogeneous catalysis and reaction engineering. His current focus is on the development of catalytic pathways for converting renewable biomass to chemicals that can serve as precursors or additives for fuels. The U.S. has an abundant supply of coal as well as renewable biomass. Coal received a lot of attention 25-30 years ago as a feedstock for liquid fuels and other chemicals, but there are two main problems with coal as an energy source which are not a factor in renewable biomass: (i) coal typically has high sulfur content (3-5 wt%), and (ii) it increases carbon dioxide in the environment. In contrast, renewable biomass is CO2-neutral, and has only a small sulfur content (less than 0.1 wt%). The chemistry of biomass conversion, on the other hand, has added complexity because of the presence of oxygen and different structures formed in natural products, which vary from source to source.
Working in collaboration with Dr. Chris Jones, this work focuses on loblolly pine and switchgrass. A number of non-enzymatic pathways are being studied to separate the basic components of the lignocellulosic feed. The aim is to develop a basic understanding of the effect of various processing variables and how the yields and formation of different species are affected. The next step is to investigate different approaches for catalytic upgrading of the chemicals obtained in the first stage. Catalytic upgrading may involve (i) removal of oxygen from the products (containing C, H, and O) obtained in the first stage, and (ii) developing catalytic pathways for tailoring the product’s molecular size so it can serve as a direct fuel additive.
RACHEL CHEN
Dr. Chen’s group is capturing the excitement of the most recent developments in biological sciences and applying the most advanced technology in engineering microbial catalysts for valuable biomolecules. Two application areas are highlighted as follows.
As molecular recognition elements, sugar moieties of glycoproteins and glycolipids play crucial roles in many biological processes, including numerous disease-causing events. As such, they are a new class of molecules with excellent therapeutic potential for a broad range of diseases such as cancer. Despite impressive progress in carbohydrate synthesis in recent years, the difficulty associated with the synthesis is still one of the most challenging obstacles in the clinical development. Dr. Chen’s group has been applying metabolic engineering tools in engineering bacterial catalysts for the synthesis of these valuable molecules. E. coli and Agrobacterium sp. were engineered to produce di- and tri-saccharides epitopes. Recently, Dr. Chen’s lab has successfully engineered both E. coli and Agrobacterium sp. for the synthesis of hyaluronan, a sugar polymer used in ophthalmic surgery and other medical procedures.
While engineering microbes for bioethanol is not new, recent scientific and technological advances in biological research, notably the “omics,” have provided powerful tools in engineering more efficient microbial catalysts. Dr. Chen’s group, in partnership with Chevron Corporation, is applying a holistic metabolic engineering approach in developing robust microbial catalysts for ethanol production. Her group is also engineering cellulolytic E. coli and other microbes for broader biorefinery applications.
CHRIS JONES
Dr. Jones is broadly interested in problems at the interface of synthetic chemistry and chemical engineering. His research group currently works in four related areas: (i) supported organic and organometallic catalysts in organic synthesis, (ii) polymerization, (iii) new materials for separations, and (iv) conversion of biomass into fuels and chemicals.
Three of these topics concern catalysis and reaction engineering. Supported organometallic catalysts are developed and optimized for important reactions used in the synthesis of complex organic molecules such as pharmaceutical precursors and fine chemicals. A special emphasis is placed on rigorously evaluating the heterogeneity and recyclability of the catalysts, with an interest in developing waste-free processes. Catalysts and processes for polymerization of olefins, by both metal-mediated catalysis and radical polymerization, are also under evaluation. In biomass conversion, Dr. Jones directs a large program in collaboration with Dr.. Pradeep Agrawal as part of the GT Strategic Energy Institute. Working with Chevron as a research partner, new routes for the synthesis of transportation fuels from pine wood are sought.
Recently, the Jones group has started programs on new materials for separations. Working with Drs. Bill Koros and Sankar Nair, they are modifying zeolites for use in polymer/zeolite mixed matrix membranes for gas separations. In addition, the Jones group has developed promising new silica-polymer hybrid materials for CO2 capture from coal-fired power plants. These materials could fulfill crucial technological needs in the fight against greenhouse gas emissions and global warming.
The Georgia Institute of Technology is one of the nation's premiere research universities. Ranked among U.S. News & World Report's top 10 public universities, Georgia Tech educates more than 16,000 students every year through its Colleges of Architecture, Computing, Engineering, Liberal Arts, Management and Sciences. Tech maintains a diverse campus and is among the nation's top producers of women and African-American engineers. The Institute offers research opportunities to both undergraduate and graduate students and is home to more than 100 interdisciplinary units plus the Georgia Tech Research Institute. During the 2003-2004 academic year, Georgia Tech reached $341.9 million in new research award funding.