Development of New Materials and Methods for Effective, Selective, and Energy-efficient Olefin/Paraffin Separation and Ethylene Detection

University Of Texas At Arlington, Arlington TX

Investigators

Abstract

Important chemical feedstocks include a group of molecules called alkenes, molecules that contain carbon-carbon double bonds. The alkenes are used in the manufacture of many important plastics and include ethylene, which is used to make polyethylene; propylene, which is used to make polypropylene; and a several others. The alkenes are produced during the refining of crude oil. However, they are always obtained as complex mixtures of alkenes and other petroleum components. In order to obtain pure alkenes, crude oil mixtures are separated using an energy-intensive distillation process. Presently, ethylene and propylene purification alone accounts for about 0.3% of the world’s total energy consumption. A more a efficient separation technique for alkenes would be of great benefit. Toward this end, Dr. Rasika Dias, University of Texas at Arlington (UTA), is supported by the Chemical Synthesis Program to develop metal compounds that are capable of separating alkenes at room temperature and pressure. The general method prepares copper compounds that bind specific alkenes and can be induced to release the alkene in a targeted way. This behavior may be used for the low energy purification of alkenes. As an ancillary effort, the copper and related silver compounds are modified to detect alkenes. This is important not only to monitor industrial environments, but also to a number of fruit and flower industries as ethylene induces the ripening of fruit (such as bananas)and the degradation of flowers. This project integrates research into the educational experience for undergraduate, graduate, and postdoctoral students, and prepares them for productive careers physical science. Professor Dias plans to recruit students from traditionally underrepresented groups including McNair and LSAMP programs, offering research opportunities in his laboratory. High-school and Community College student mentoring activities are also planned. Professor Dias organizes a symposium at UTA inviting Assistant Professors and Postdoctoral Fellows to meet and share their research findings. He also organizes a workshop on X-ray crystallography to benefit area crystallographers and utilizes the UTA Planetarium facilities to educate and excite young audiences (including pre-K) in science. In this project, copper and silver complexes of multi-dentate pyrazolate ligands are synthesized and their abilities to selectively and reversibly bind ethylene, propylene, and butane are evaluated. A systematic study is undertaken to discern how the overall heat of the olefin-binding can be managed through modification of the supporting ligands. The goal of this research is to design compounds that facilitate olefin-paraffin separations. A second focus concentrates on the development of sensors to detect ethylene. In this effort, a family of luminescent copper and silver pyrazolate complexes that produce optical signals upon exposure to olefins are prepared. Overall, the project investigates the structure, bonding, and reactivity of late d-block complexes with labile metal-ligand interactions. Students contributing to this project will gain valuable experience in synthesis, modern characterization techniques, and critical thinking. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.