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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Functionalized Metal-Organic Frameworks for Catalytic Applications

Xie, Feng 10 1900 (has links)
The development and design of efficient catalysts are essential for catalytic energy technologies, accompanied with the fundamental understanding of structure-property relationships of these catalysts. Metal-organic frameworks (MOFs), as the new class of promising catalysts, have been intensively investigated primarily in their fundamental electrochemistry and the broad spectrum of catalytic applications due to their structural flexibility, tailorable crystalline, and multi-functionality. In this work, we combine experiments and mechanism investigation to gain a fundamental understanding of how the surface property and the structure of MOFs affect their catalytic performance. With the aim of material design for MOFs catalysts, we developed two novel superhydrophilic and aerophobic metal-organic frameworks (AlFFIVE-1-Ni MOFs and FeFFIVE-1-Ni MOFs) used as electrocatalysts for the first time during oxygen evolution reactions (OER). Under the facilitation of hydrophilicity and aerophobicity, developed FeFFIVE-1-Ni MOFs electrocatalysts deliver optimal OER performance, better than that of the state-of-art RuO2 and referred NiFe-BDC MOFs electrocatalysts. Most importantly, the practical strategy demonstrated that the hydrophilic and aerophobic structure of MOFs does indeed deliver the optimal electrocatalytic performance. With the aim of investigating the structural transformation process of metal-organic framework, we used a series of advanced characterization techniques to monitor the structure evolution and defects presence for post-heating treated UiO-66 MOFs. The structural and electronic features of UiO-66 MOFs were intensely studied in their hydroxylated, dehydroxylated, defected, and pyrolytic forms. Meanwhile, one concept about the framework situation, quasi-MOF (like a transition state, defined high activation along the structure evolution corresponding to the presence of many defects), was presented and demonstrated. Compared with pristine UiO-66 MOF, the Quasi-MOF with the presence of active defects showed enhanced catalytic activity on the Meerwein-Ponndorf-Verley reduction reaction, which offers an opportunity to understand the structure-property relationship along with the structure evolution process of UiO-66 MOFs.
2

Transferring pharmaceutical batch technology to continuous flow

Peterson, Olga Yuris 28 February 2011 (has links)
The current trend in the pharmaceutical industry is towards continuous flow processes. Continuous flow reactor technology can produce a cheaper, better quality product at reduced energy and environmental cost through more efficient mass and heat transfer. It also enables a simplified and faster approach to bulk production by scaling out as opposed to scaling up. The research presented here focuses on the configuration and installation of a continuous flow system into the laboratory, and the transfer of a Meerwein-Ponndorf-Verley (MPV) reduction from batch to continuous mode. The Corning® glass continuous flow reactor in our laboratory utilizes specially-designed mixing structures for enhanced mass transfer. Additionally, the glass reactor offers nonreactivity and corrosion resistance over a wide range of temperature and pressure, which conventional steel reactors do not allow. The MPV reduction is a well-known method to prepare primary and secondary alcohols from aldehydes and ketones, respectively. The traditional MPV reduction protocol (Al(OiPr)₃ in isopropanol) was modified to enable the technological transfer from batch to continuous mode. This is the first time MPV reduction reactions were carried out in continuous mode. As a result, the MPV reduction of the model compound, benzaldehyde, was successfully conducted with 60% less catalyst and product yield was improved up to 20% (average of 10%) in continuous flow reactions as compared to current batch technology. These results are being used to develop a technology roadmap for the pharmaceutical industry to implement continuous flow processes in their manufacturing operations.

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