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You searched for +publisher:"Georgia Tech" +contributor:("Dr. E. Kent Barefield"). Showing records 1 – 2 of 2 total matches.

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Georgia Tech

1. Kutukcu, Mehmet Nuri. Synthesis and Characterization of Low and Negative Thermal Expansion Materials.

Degree: MS, Chemistry and Biochemistry, 2005, Georgia Tech

URL: http://hdl.handle.net/1853/7636 

The preparation and thermophysical properties of some In(I), Ga(I) and Ag(I) substituted NZP type materials were explored. Many compositions with the NZP framework show low and negative thermal expansion. Previously reported material, GaZr2(PO4(3, transforms from one NZP related phase into another NZP type phase due to oxidation under air above 300 °C. In addition, it exhibits hysteresis under inert atmosphere; the cell parameters are different on heating and cooling cycles for a given temperature. The synthesis, and characterization of a new material, InZr2(PO4)3, is outlined. It crystallizes in space group R -3 c. In addition, as GaZr2(PO4)3, it oxidizes above 300 °C under air and exhibits hysteresis under inert atmosphere. Furthermore, the synthesis of AgTixZr2-x(PO4)3 solid solution compositions, their ion exchange characteristics with Ga(I) and their thermophysical properties are described. Thermal expansion anisotropy (the difference between a and c ) of the solid solutions decreases as the bigger ion, Zr4+, is substituted by the smaller one, Ti4+. Thermal expansion characteristics of GaZr2(PO4)3, InZr2(PO4)3 and AgZr2(PO4)3 are compared with MZr2(PO4)3 ( M = Li, Na, K, Rb, Cs). Ionic radii for Ga(I) and In(I) in a six coordinate oxygen environment were proposed. Advisors/Committee Members: Dr. Angus P. Wilkinson (Committee Chair), Dr. E. Kent Barefield (Committee Member), Dr. Z. John Zhang (Committee Member).

Subjects/Keywords: Ion exchange; Thermal behavior; X-ray diffraction; Negative thermal expansion; Univalent Ga and In

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Kutukcu, M. N. (2005). Synthesis and Characterization of Low and Negative Thermal Expansion Materials. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/7636

Chicago Manual of Style (16th Edition):

Kutukcu, Mehmet Nuri. “Synthesis and Characterization of Low and Negative Thermal Expansion Materials.” 2005. Masters Thesis, Georgia Tech. Accessed March 04, 2021. http://hdl.handle.net/1853/7636.

MLA Handbook (7th Edition):

Kutukcu, Mehmet Nuri. “Synthesis and Characterization of Low and Negative Thermal Expansion Materials.” 2005. Web. 04 Mar 2021.

Vancouver:

Kutukcu MN. Synthesis and Characterization of Low and Negative Thermal Expansion Materials. [Internet] [Masters thesis]. Georgia Tech; 2005. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/1853/7636.

Council of Science Editors:

Kutukcu MN. Synthesis and Characterization of Low and Negative Thermal Expansion Materials. [Masters Thesis]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/7636


Georgia Tech

2. Richardson, John Michael. Distinguishing between surface and solution catalysis for palladium catalyzed C-C coupling reactions: use of selective poisons.

Degree: PhD, Chemical and Biomolecular Engineering, 2008, Georgia Tech

URL: http://hdl.handle.net/1853/22704 

This work focuses on understanding the heterogeneous/homogeneous nature of the catalytic species for a variety of immobilized metal precatalysts used for C-C coupling reactions. These precatalysts include: (i) tethered organometallic palladium pincer complexes, (ii) an encapsulated small molecule palladium complex in a polymer matrix, (iii) mercapto-modified mesoporous silica metalated with palladium acetate, and (iv) amino-functionalized mesoporous silicas metalated with Ni(II). As part of this investigation, the use of metal scavengers as selective poisons of homogeneous catalysis is introduced and investigated as a test for distinguishing heterogeneous from homogeneous catalysis. The premise of this test is that insoluble materials functionalized with metal binding sites can be used to selectively remove soluble metal, but will not interfere with catalysis from immobilized metal. In this way the test can definitely distinguish between surface and solution catalysis of immobilized metal precatalysts. This work investigates three different C-C coupling reactions catalyzed by the immobilized metal precatalysts mentioned above. These reactions include the Heck, Suzuki, and Kumada reactions. In all cases it is found that catalysis is solely from leached metal. Three different metal scavenging materials are presented as selective poisons that can be used to determine solution vs. surface catalysis. These selective poisons include poly(vinylpyridine), QuadrapureTM TU, and thiol-functionalized mesoporous silica. The results are contrasted against the current understanding of this field of research and subtleties of tests for distinguishing homogeneous from heterogeneous catalysis are presented and discussed. Advisors/Committee Members: Dr. Christopher W. Jones (Committee Chair), Dr. E. Kent Barefield (Committee Member), Dr. Marcus Weck (Committee Member), Dr. Pradeep Agrawal (Committee Member), Dr. Rachel Chen (Committee Member).

Subjects/Keywords: Palladium catalysis; Cross coupling reaction; Heterogeneous vs. homogeneous; Selective poisoning; Palladium catalysts; Heterogeneous catalysis; Catalysis; Catalyst poisoning

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Richardson, J. M. (2008). Distinguishing between surface and solution catalysis for palladium catalyzed C-C coupling reactions: use of selective poisons. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/22704

Chicago Manual of Style (16th Edition):

Richardson, John Michael. “Distinguishing between surface and solution catalysis for palladium catalyzed C-C coupling reactions: use of selective poisons.” 2008. Doctoral Dissertation, Georgia Tech. Accessed March 04, 2021. http://hdl.handle.net/1853/22704.

MLA Handbook (7th Edition):

Richardson, John Michael. “Distinguishing between surface and solution catalysis for palladium catalyzed C-C coupling reactions: use of selective poisons.” 2008. Web. 04 Mar 2021.

Vancouver:

Richardson JM. Distinguishing between surface and solution catalysis for palladium catalyzed C-C coupling reactions: use of selective poisons. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/1853/22704.

Council of Science Editors:

Richardson JM. Distinguishing between surface and solution catalysis for palladium catalyzed C-C coupling reactions: use of selective poisons. [Doctoral Dissertation]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/22704

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