자료유형  

 학위논문

Control Number  

0016932869

International Standard Book Number  

9798379851965

Dewey Decimal Classification Number  

600

Main Entry-Personal Name  

Wang, Qi.

Publication, Distribution, etc. (Imprint  

[S.l.] : Purdue University., 2022

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2022

Physical Description  

1 online resource(114 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 85-01, Section: B.

General Note  

Advisor: Wei, Alexander.

Dissertation Note  

Thesis (Ph.D.)--Purdue University, 2022.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Summary, Etc.  

요약Advances in nanomaterials research have stoked interests in the design of dispersible catalysts for specific organic transformations, with higher reaction efficiency or lower burden in post-reaction waste processing. Multicomponent heterogeneous catalysts generally offer higher catalytic performance than single-component catalysts, with metal-substrate interactions (MSI) playing a key role in their performance. This thesis focuses on silver-iron-oxide particles as heterogeneous catalysts, starting with a literature survey (Chapter 1) followed by the synthesis and catalytic properties of two novel types of Ag-Fe3O4 particles that show strong potential for mediating C(sp2 )-H arylation reactions (Chapters 2 and 3). Silver and especially iron oxide are much less expensive than other types of metals, and the magnetic properties of the Fe3O4support transferability and reuse of the active catalytic species which enables us to reduce the ratio of catalyst to reactant. These features address multiple goals outlined by the principles of green chemistry. The arylation of heterocyclic compounds is frequently used in the preparation of organic dyes, polymers, and pharmaceutical intermediates, and is a useful benchmark reaction for comparing our cross-coupling catalyst with those from prior reports.In Chapter 2, we describe the synthesis of colloidal silver-iron-oxide (SIO) and investigate its conversion into an efficient catalyst for C(sp2 )-H arylation using novel modes of activation. This includes electrochemical activation using mild cathodic potentials, and photoactivation using a white light source. Both methods dramatically improve the efficacy of colloidal SIO as a catalyst for the cross coupling of diazonium salts with heteroaromatic rings at room temperature. Highresolution transmission electron microscopy analysis reveals that the SIO particles are primarily composed of colloidal Ag that are coated with nanosized islands of Fe3O4. The SIO catalysts are magnetically responsive and can be collected and reused multiple times, without requiring reactivation. The SIO is susceptible to acid degradation but can be preserved with neutralization by added base during reaction cycling.In Chapter 3, we describe a second-generation catalyst in which Fe3O4 microspheres serves as the supporting substrate for Ag islands, with synthetic control over Ag size distribution. This material does not require any activation for cross-coupling catalysis, which can be attributed to better charge transfer between the Ag islands and Fe3O4 substrate. A comparison of Ag-Fe3O4 microspheres with different Ag/Fe ratios suggests that catalytic activity correlates with smaller particle sizes, where the strongest charge-transfer interactions are likely to occur. The role of MSI between Ag and Fe3O4 was further explored using X-ray absorption spectroscopy. The secondgeneration Ag-Fe3O4 catalysts are far more robust than the previous version and are better able to withstand acidic degradation, with less mass loss after multiple reaction cycles and no loss in catalytic function. Lastly, we have found that Ag-Fe3O4microspheres can also be an efficient catalyst for the reduction of nitro groups into amines, and describe progress toward the one-pot conversion of nitroarenes into cross-coupling products.

Subject Added Entry-Topical Term  

Metals.

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Pollutants.

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Acids.

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Oxidation.

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Nanoparticles.

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Solvents.

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Conversion.

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Adsorption.

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Microscopy.

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Silver.

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Chemistry.

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Phenols.

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Catalysis.

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Hydrogenation.

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Photocatalysis.

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Quantum dots.

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Atoms & subatomic particles.

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Ethanol.

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Atomic physics.

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Nanotechnology.

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Organic chemistry.

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Physical chemistry.

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Physics.

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Quantum physics.

Added Entry-Corporate Name  

Purdue University.

Host Item Entry  

Dissertations Abstracts International. 85-01B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:644024