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

重要的化学原料包括一组称为烯烃的分子，即含有碳-碳双键的分子。烯烃用于制造许多重要的塑料，包括用于制造聚乙烯的乙烯；用于制造聚丙烯的丙烯；以及其他几种。这些烯烃是在原油精炼过程中产生的。然而，它们总是以烯烃和其他石油组分的复杂混合物的形式获得。为了获得纯的烯烃，原油混合物使用能量密集型蒸馏过程进行分离。目前，仅乙烯和丙烯净化一项就占世界总能耗的0.3%左右。一种更有效的烯烃分离技术将是非常有益的。为此，德克萨斯大学阿灵顿分校(UTA)的Rasika Dias博士得到了化学合成计划的支持，开发能够在常温常压下分离烯烃的金属化合物。通常的方法制备结合特定烯烃的铜化合物，并且可以被诱导以靶向的方式释放烯烃。这一行为可用于烯烃的低能提纯。作为辅助工作，铜和相关的银化合物被修饰以检测烯烃。这不仅对监测工业环境很重要，而且对一些水果和花卉行业也很重要，因为乙烯会导致水果(如香蕉)成熟和花朵退化。该项目将研究融入到本科生、研究生和博士后的教育经验中，并为他们从事富有成效的物理学职业做好准备。迪亚斯教授计划从麦克奈尔和LSAMP项目等传统上代表性较低的群体中招收学生，在他的实验室提供研究机会。还计划开展高中和社区大学学生辅导活动。迪亚斯教授在UTA组织了一次研讨会，邀请助理教授和博士后研究员见面并分享他们的研究成果。他还组织了一次X射线结晶学研讨会，以帮助区域结晶学家，并利用UTA天文馆的设施来教育和激发年轻观众(包括学前班)的科学。在这个项目中，合成了多齿吡唑配体的铜和银配合物，并评估了它们选择性和可逆结合乙烯、丙烯和丁烷的能力。进行了一项系统的研究，以了解如何通过修饰支持配体来管理烯烃结合的总热。这项研究的目标是设计有助于烯烃-烷烃分离的化合物。第二个重点是开发检测乙烯的传感器。在这项工作中，制备了一系列发光的铜和银吡唑配合物，它们在接触到烯烃时会产生光学信号。总体而言，该项目研究了具有不稳定的金属-配体相互作用的晚期d-嵌段络合物的结构、成键和反应活性。为这个项目做出贡献的学生将获得在合成、现代表征技术和批判性思维方面的宝贵经验。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.