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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

Porous Organic Polymer-based Nanotraps for Metal Resource Recovery/Extraction from Water

Song, Yanpei 05 1900 (has links)
The recovery processes of critical metals from multiple sources have turned more and more attention due to the increasing demand and consumption of them in modern industry. Many metals are used as significant components in manufacturing of a variety of products and equipment, playing significant roles in the economic security and national security; those metals involve rare earth elements (REEs), precious metals which include gold, silver, and platinum group metals (PGMs), and other valuable metals such as lithium, uranium, nickel, et al. The traditional approach to obtaining the above metals is by hardrock mining of natural ores via chemical and physical processes. However, this method of mining and refining metals from minerals is usually energy-consuming, costly, and environmental-destructive. Thus, various approaches to extracting or recycling target metals from the seawater or the solution of secondary resources as an alternative to traditional hardrock mining have been developed, and thereinto, using functional porous adsorbents to selectively capture specific metal ions from the aqueous resources has attracted increasing attention due to its outstanding merits such as high efficiency, energy-saving process, low cost, and reduced environmental impacts
2

Design and Synthesis of Dehydrobenzoannulene Based Covalent Organic Frameworks

Crowe, Jonathan William 30 August 2017 (has links)
No description available.
3

Metal Organic Frameworks (MOFs) and Porous Organic Polymers (POPs) for Heterogeneous Asymmetric Catalysis

Ji, Youngran 01 January 2015 (has links)
The administration of enantiopure drugs brings advantages such as improved efficacy, more predictable pharmacokinetics and reduced toxicity from the point of view of the pharmaceutical area.[1] For this reason, a tremendous amount of supply and demand for enantiomeric pure compounds has been shown not only in market, but industry and academia.[2-4] According to the industry publication Genetic Engineering and Biotechnology News (GEN) in 2014, 22 billion dollars were accounted for enantiopure form of drugs such as Sovaldi® (Sofosbuvir), Crestor® (Rosuvastatin), and Advair® (fluticasone/salmeterol). The fact that one enantiomer can be pharmacologically effective whereas the other enantiomer can be inactive or display non-desirable activity, chiral resolution and asymmetric synthesis research has broken out in recent years to obtain one desired stereoisomer. Enormous amounts of well-organized and rationalized research results for higher enantiomeric selectivity and efficiency has been reported with diverse chiral ligands and transition metals in academia.[5-10] However novelty-driven results from academic area does not meet the requirement in industry field for the practical issue, especially tedious separation process that require high cost and effort. In addition, methodologies developed with privileged chiral ligands and transition metal complexes leave a concern like undesired residue of trace amount of toxic metals in the products. In this dissertation, two types of heterogeneous asymmetric catalyst were investigated to find the alternative that accommodates industrial requirement to obtain enantiomeric pure compounds and novelty-driven academic demands. Firstly, constructions of rationally designed metal organic frameworks (MOFs) using chiral BINOL-derived phosphoric acid ligands were achieved. Overall, catalytic reactions with ocMOFs showed lower enatioselectivity than their homogeneous counterparts, but one of the MOFs, ocMOF-1, was found to exhibit improved enantioselectivity than its homogeneous counterpart in the context of transfer hydrogenation reaction of benzoxazine. Lower enatioselectivity with ocMOFs was rationalized by the chiral environment change by the formation of frameworks in a computational study. In addition, self-supported heterogenization of chiral BINOL-phosphoric acid was achieved by the Yamamoto coupling reaction, and by using catalytically active ocPOP-1 having nanoscopic channels, enantioselectivity was obtained up to 48% in transfer hydrogenation of N-PMP ketimine. Although extension of substituent groups at 3, 3' positions was expected to bring enhanced steric hindrance and to influence to enantioselectivity positively, lack of spatially well-defined interactions induced by this chiral environment change might have lowered the enantiomeric selectivity of the catalytic reaction using ocPOP-1 than its counterpart.
4

DESIGNED SYNTHESIS OF NANOPOROUS ORGANIC POLYMERS FOR SELECTIVE GAS UPTAKE AND CATALYTIC APPLICATIONS

Arab, Pezhman 01 January 2015 (has links)
Design and synthesis of porous organic polymers have attracted considerable attentions during the past decade due to their wide range of applications in gas storage, gas separation, energy conversion, and catalysis. Porous organic polymers can be pre-synthetically and post-synthetically functionalized with a wide variety of functionalities for desirable applications. Along these pursuits, we introduced new synthetic strategies for preparation of porous organic polymers for selective CO2 capture. Porous azo-linked polymers (ALPs) were synthesized by an oxidative reaction of amine-based monomers using copper(I) as a catalyst which leads to azo-linkage formation. ALPs exhibit high surface areas of up to 1200 m2 g-1 and have high chemical and thermal stabilities. The nitrogen atoms of the azo group can act as Lewis bases and the carbon atom of CO2 can act as a Lewis acid. Therefore, ALPs show high CO2 uptake capacities due to this Lewis acid-based interaction. The potential applications of ALPs for selective CO2 capture from flue gas, natural gas, and landfill gas under pressure-swing and vacuum swing separation settings were studied. Due to their high CO2 uptake capacity, selectivity, regenerability, and working capacity, ALPs are among the best porous organic frameworks for selective CO2 capture. In our second project, a new bis(imino)pyridine-linked porous polymer (BIPLP-1) was synthesized and post-synthetically functionalized with Cu(BF4)2 for highly selective CO2 capture. BIPLP-1 was synthesized via a condensation reaction between 2,6-pyridinedicarboxaldehyde and 1,3,5-tris(4-aminophenyl)benzene, wherein the bis(imino)pyridine linkages are formed in-situ during polymerization. The functionalization of the polymer with Cu(BF4)2 was achieved by treatment of the polymer with a solution of Cu(BF4)2 via complexation of copper cations with bis(imino)pyridine moieties of the polymer. BF4- ions can act Lewis base and CO2 can act as a Lewis acid; and therefore, the functionalized polymer shows high binding affinity for CO2 due to this Lewis acid-based interaction. The functionalization of the pores with Cu(BF4)2 resulted in a significant enhancement in CO2 binding energy, CO2 uptake capacity, and CO2 selectivity values. Due to high reactivity of bis(imino)pyridines toward transitions metals, BIPLP-1 can be post-synthetically functionalized with a wide variety of inorganic species for CO2 separation and catalytic applications.

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