Collaborative Research: RUI: Development and Fundamental Studies of N2-absorbing, Iron-phosphine-containing Polymers for Pressure Swing Purification of Natural Gas

Pacific University, Forest Grove OR

Investigators

Abstract

Natural gas is an important source of energy in the United States. However, some of the U.S. natural gas reserves are contaminated with nitrogen gas to the extent that it is necessary to remove the contaminant before it is used. Under the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Dr. Gohdes at Pacific University and Dr. Tyler at the University of Oregon combine molecular chemistry synergistically with polymer science to design and synthesize novel metal-templated polymers (MTPs) that will be useful as long-lived absorbents for the purification of natural gas. The fundamental knowledge gained from this project has broader scientific implications in other important areas such as catalysis and sensor design. Undergraduate and graduate students working on this project receive training in experimental design and a broad array of synthetic and analytical techniques. This project is expected to provide training of STEM educators through vehicles such as a summer workshop on Informal Science Education (ISE) where students interested in science education learn techniques for effectively communicating with the public in venues such as science museums. Prior work in the Tyler lab at the University of Oregon showed that water-soluble trans-Fe(P2)2(X)(Cl)-type complexes (X = Cl, H; P2 = a water-soluble bidentate phosphine) can successfully bind dinitrogen reversibly under conditions suitable for a pressure-swing separation process. In this project, Dr. Gohdes and Dr. Tyler aim to enhance the stability of the nitrogen binding Fe(II) complexes by encapsulating them in a polymer matrix, forming MTPs around the nitrogen binding motif. Another approach to enhance stability of the nitrogen binding complexes is by replacing the bidentate phosphines with macrocyclic, tetradentate phosphines. These groups collaboratively perform research to study the thermodynamics and kinetics of the nitrogen-binding reactions of the iron complexes and MTPs. A fundamental understanding of how the properties of the polymer affect the intrinsic reactivity of the metal center is important for the design and optimization of the next generation nitrogen-absorbing materials.