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Georgia Tech
1.
Wilson, Benn Charles.
Silica-Supported Organic Catalysts For The Synthesis Of Biodegradable Polymers.
Degree: MS, Chemical Engineering, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/4918 
► Aliphatic polyesters such as polycaprolactone and polylactide have received more attention in recent years for their use in biomedical applications because of their biodegradable nature.…
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▼ Aliphatic polyesters such as polycaprolactone and polylactide have received more attention in recent years for their use in biomedical applications because of their biodegradable nature. These polymers are often synthesized using homogeneous metal complexes. Unfortunately, using homogeneous metals as catalysts leads to metal contamination in the product polymer, a result which is highly undesirable in a polymer intended for biomedical use.
More recent work has shown that these polymers can be synthesized using homogeneous metal-free complexes. These catatlysts are generally less active than metal catalysts, and although they do not contaminate the polymer with metal residue, they are still difficult to recover and hence recycle for further use.
In this work, we attempted to create a metal-free, silica-supported catalyst for use in the synthesis of polycaprolactone or polylactide.
Ultimately, n-propylsulfonic acid-functionalized porous and nonporous silica materials are evaluated in the ring-opening polymerization of epsilon-caprolactone. All catalysts allow for the controlled polymerization of the monomer, producing polymers with controlled molecular weights and narrow polydispersities. Polymerization rates are low, with site-time-yields generally one to three orders of magnitude lower than metal-based systems. The catalysts are easily recovered from the polymerization solution after use and are shown to contain significant residual adsorbed polymer. Solvent extraction techniques are useful for removing most of the polymer, although the extracted solids are not effective catalysts in recycle experiments. These new materials represent a green alternative to traditional metal-based catalysts, as they are recoverable and leave no metal residues in the polymer.
Advisors/Committee Members: Dr. Chris Jones (Committee Chair), Dr. Joseph Schork (Committee Member), Dr. Marcus Weck (Committee Member).
Subjects/Keywords: Organic catalysts; Metal free catalysts; Biodegradable polymers; Lactide; Caprolactone; Silica-supported catalysts; Silica; Polymers in medicine; Catalysts; Biocompatibility
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APA (6th Edition):
Wilson, B. C. (2004). Silica-Supported Organic Catalysts For The Synthesis Of Biodegradable Polymers. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/4918
Chicago Manual of Style (16th Edition):
Wilson, Benn Charles. “Silica-Supported Organic Catalysts For The Synthesis Of Biodegradable Polymers.” 2004. Masters Thesis, Georgia Tech. Accessed January 23, 2021.
http://hdl.handle.net/1853/4918.
MLA Handbook (7th Edition):
Wilson, Benn Charles. “Silica-Supported Organic Catalysts For The Synthesis Of Biodegradable Polymers.” 2004. Web. 23 Jan 2021.
Vancouver:
Wilson BC. Silica-Supported Organic Catalysts For The Synthesis Of Biodegradable Polymers. [Internet] [Masters thesis]. Georgia Tech; 2004. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/1853/4918.
Council of Science Editors:
Wilson BC. Silica-Supported Organic Catalysts For The Synthesis Of Biodegradable Polymers. [Masters Thesis]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/4918
Georgia Tech
2.
Vargas, Marian.
Design of New Polyester Architectures through Copolymerization, Crosslinking, and Diels-Alder Grafting.
Degree: PhD, Chemistry and Biochemistry, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/5194
► The compound 2,6-anthracenedicarboxylic acid is used as a comonomer for the synthesis of poly(ethylene terephthalate). The resulting copolymers are characterized and further functionalized by Diels-Alder…
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▼ The compound 2,6-anthracenedicarboxylic acid is used as a comonomer for the synthesis of poly(ethylene terephthalate). The resulting copolymers are characterized and further functionalized by Diels-Alder grafting or crosslinking through the anthracenate unit. Diels-Alder reaction is used to graft small molecules and oligomers endcapped with maleimide as dienophiles on to poly(ethylene terephthalate-co-2,6-anthracenedicarboxylate),PET-co-A. Maleimide-capped poly(ethylene glycol) is grafted onto PET-co-A to improved its hydrophilicity.
2,6-Anthracenedicarboxylic acid is also incorporated into the known liquid crystalline polymer, LCP, poly(4-oxybenzoate-co-1,4-phenylene isophthalate), HIQ40. The resulting copolymer, poly(4-oxybenzoate-co-1,4-phenylene isophthalate-co-2,6-phenylene anthracenate), HIQ40-co-A, shows LCP behavior. These HIQ40-co-A copolymers are grafted with maleimide end-capped monomers and polymers andcrosslinked with bismaleimides through a Diels-Alder mechanism.
Advisors/Committee Members: Dr. David M. Collard (Committee Chair), Dr. Charles Liota (Committee Member), Dr. David Schiraldi (Committee Member), Dr. Marcus Weck (Committee Member), Dr. Satish Kumar (Committee Member).
Subjects/Keywords: Anthracenate; HIQ40; Diels-Alder grafting; Crosslinking; PET; Polyester; Diels-Alder reaction; Polyethylene terephthalate; Copolymers; Crosslinked polymers
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APA (6th Edition):
Vargas, M. (2004). Design of New Polyester Architectures through Copolymerization, Crosslinking, and Diels-Alder Grafting. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/5194
Chicago Manual of Style (16th Edition):
Vargas, Marian. “Design of New Polyester Architectures through Copolymerization, Crosslinking, and Diels-Alder Grafting.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 23, 2021.
http://hdl.handle.net/1853/5194.
MLA Handbook (7th Edition):
Vargas, Marian. “Design of New Polyester Architectures through Copolymerization, Crosslinking, and Diels-Alder Grafting.” 2004. Web. 23 Jan 2021.
Vancouver:
Vargas M. Design of New Polyester Architectures through Copolymerization, Crosslinking, and Diels-Alder Grafting. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/1853/5194.
Council of Science Editors:
Vargas M. Design of New Polyester Architectures through Copolymerization, Crosslinking, and Diels-Alder Grafting. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/5194
Georgia Tech
3.
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…
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▼ 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 (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 January 23, 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. 23 Jan 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 Jan 23].
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
Georgia Tech
4.
Das, Prolay.
Long-Range Charge Transfer in Plasmid DNA Condensates and DNA-Directed Assembly of Conducting Polymers.
Degree: PhD, Chemistry and Biochemistry, 2007, Georgia Tech
URL: http://hdl.handle.net/1853/19856
► Long-distance radical cation transport was studied in DNA condensates where linearized pUC19 plasmid was ligated to an oligomer and transformed into DNA condensates with spermidine.…
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▼ Long-distance radical cation transport was studied in DNA condensates where linearized pUC19 plasmid was ligated to an oligomer and transformed into DNA condensates with spermidine. DNA condensates were detected by Dynamic Light Scattering and observed by Transmission Electron Microscopy. Introduction of charge into the condensates causes long-distance charge migration, which is detected by reaction at the remote guanines. The efficiency of charge migration in the condensate is significantly less than it is for the corresponding oligomer in solution. This result is attributed to a lower mobility for the migrating radical cation in the condensate, caused by inhibited formation of charge-transfer-effective states. Radical cation transport was also studied in DNA condensates made from an oligomer sandwiched between two linearized plasmids by double ligation. Unlike the single ligated plasmid condensates, the efficiency of charge migration in the double ligated plasmid-condensates is high, indicative of local structural and conformational transformation of the DNA duplexes.
Organic monomer units having extended ð-conjugation as part of a long conducting polymer was synthesized and characterized. The monomer units were covalently attached to particular positions in DNA oligonucleotides by either the convertible nucleotide approach or by phosphoramidite chemistry. Successful attachment of the monomer units to DNA were confirmed by mass spectral analysis. The DNA-conjoined monomer units can self assemble in the presence of complementary sequences which act as templates that can control polymer formation and structure. By this method the para-direction of the polymer formation can be enforced and may be used to generate materials having nonrecurring, irregular structures.
Advisors/Committee Members: Dr. Gary B. Schuster (Committee Chair), Dr. David M. Collard (Committee Member), Dr. Donald Doyle (Committee Member), Dr. Marcus Weck (Committee Member), Dr. Uzi Landman (Committee Member).
Subjects/Keywords: DNA charge transfer; Conducting polymers; Radical cation; Self assembly; Conducting polymers; Charge tranfer in biology; Cations; DNA; Self-organizing systems
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APA (6th Edition):
Das, P. (2007). Long-Range Charge Transfer in Plasmid DNA Condensates and DNA-Directed Assembly of Conducting Polymers. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/19856
Chicago Manual of Style (16th Edition):
Das, Prolay. “Long-Range Charge Transfer in Plasmid DNA Condensates and DNA-Directed Assembly of Conducting Polymers.” 2007. Doctoral Dissertation, Georgia Tech. Accessed January 23, 2021.
http://hdl.handle.net/1853/19856.
MLA Handbook (7th Edition):
Das, Prolay. “Long-Range Charge Transfer in Plasmid DNA Condensates and DNA-Directed Assembly of Conducting Polymers.” 2007. Web. 23 Jan 2021.
Vancouver:
Das P. Long-Range Charge Transfer in Plasmid DNA Condensates and DNA-Directed Assembly of Conducting Polymers. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/1853/19856.
Council of Science Editors:
Das P. Long-Range Charge Transfer in Plasmid DNA Condensates and DNA-Directed Assembly of Conducting Polymers. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/19856
Georgia Tech
5.
Nayak, Satish Prakash.
Design, Synthesis and Characterization of Multiresponsive Microgels.
Degree: PhD, Chemistry and Biochemistry, 2005, Georgia Tech
URL: http://hdl.handle.net/1853/6845
► This thesis is geared towards using hydrogel nanoparticles in various biotechnological applications. The polymer that was used in making these nanoparticles was poly(N-isopropylacrylamide), which is…
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▼ This thesis is geared towards using hydrogel nanoparticles in various biotechnological applications. The polymer that was used in making these nanoparticles was poly(N-isopropylacrylamide), which is a thermoresponsive polymer. These particles were used in making fast responsive polymer films, which can be used in optics. It was observed that the rate of deswelling increased as the concentration of the nanoparticles in the film was increased. These particles were also used in making photoresponsive materials. In this case a photoresponsive dye (malachite green) was conjugated to these nanoparticles and in presence of light of appropriate wavelength the particles undergo a phase transition. A core/shell construct was synthesized where the core was composed of degradable cross-links and the shell of composed of non-degradable cross-links. The degradable cross-linker had vicinal diols, which can be cleaved by sodium periodate. Hence after degrading the core, hollow particles were obtained. Zwitterionic particles were made by incorporating a cationic and anionic comonomer. These microgels go from a positively charged state to zwitterionic to negatively charged state on increasing the pH. One of the important potential applications for these microgels is drug delivery. Microgels were used for targeting cancer cells. Folic acid was used as the targeting ligand. The microgels were conjugated with folic acid and were able to target cells that overexpress folate receptors. In one other application core/shell microgels were made which exhibit pore-size dependent permeation of proteins.
Advisors/Committee Members: Dr. L. Andrew Lyon (Committee Chair), Dr. Christopher W. Jones (Committee Member), Dr. Jiri Janata (Committee Member), Dr. Marcus Weck (Committee Member), Dr. Nicholas V. Hud (Committee Member).
Subjects/Keywords: pNIPAm; Core/Shell; Nanoparticles; Hydrogels; Polymers; Thin films; Polymers Thermal properties; Polymers Optical properties; Nanoparticles Synthesis; Colloids
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APA (6th Edition):
Nayak, S. P. (2005). Design, Synthesis and Characterization of Multiresponsive Microgels. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/6845
Chicago Manual of Style (16th Edition):
Nayak, Satish Prakash. “Design, Synthesis and Characterization of Multiresponsive Microgels.” 2005. Doctoral Dissertation, Georgia Tech. Accessed January 23, 2021.
http://hdl.handle.net/1853/6845.
MLA Handbook (7th Edition):
Nayak, Satish Prakash. “Design, Synthesis and Characterization of Multiresponsive Microgels.” 2005. Web. 23 Jan 2021.
Vancouver:
Nayak SP. Design, Synthesis and Characterization of Multiresponsive Microgels. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/1853/6845.
Council of Science Editors:
Nayak SP. Design, Synthesis and Characterization of Multiresponsive Microgels. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/6845
Georgia Tech
6.
Shiels, Rebecca Anne.
Synthesis, characterization, and evaluation of silica and polymer supported catalysts for the production of fine chemicals.
Degree: PhD, Chemical Engineering, 2008, Georgia Tech
URL: http://hdl.handle.net/1853/29629
► Catalysis is an important field of study in chemical engineering and chemistry due to its application in a vast number of chemical transformations. Traditionally, catalysts…
(more)
▼ Catalysis is an important field of study in chemical engineering and chemistry due to its application in a vast number of chemical transformations. Traditionally, catalysts have been developed as homogeneous molecular species or as heterogeneous insoluble materials. While homogeneous catalysts are typically very active and selective, they are difficult to recover. Conversely, heterogeneous catalysts are easy to recover and reuse, but they generally are less selective. To address these issues, the immobilization of homogeneous catalyst analogs onto solid supports has been a subject of research for the past few decades. Nonetheless, the effects of immobilization are still not completely predictable, and so continued effort is required to develop new immobilized catalysts as well as to develop a better understanding of how different parameters affect catalytic behavior.
This dissertation presents the synthesis, characterization, and evaluation of new immobilized catalysts for different applications. First, a solid base catalyst supported on silica was developed and studied in the synthesis of cyclic carbonates from epoxides and carbon dioxide. Next, polymer and silica supported vanadium Schiff base catalysts were developed and evaluated for use in the oxidative kinetic resolution of alpha-hydroxy esters, an enantioselective reaction. Lastly, salen catalyst analogs with amine reactive functional groups were synthesized and characterized for grafting onto aminosilicas with different degrees of amine group isolation. The grafted catalysts were then tested to determine how catalyst spacing on the surface affects their behavior. Throughout the presentation of these results, comparisons are made amongst the new supported catalysts and relevant existing catalysts to discern general trends which could be applied to a wider range of immobilized catalysts. Finally, research opportunities for further improvements in these areas are suggested.
Advisors/Committee Members: Dr. Christopher Jones (Committee Chair), Dr. Dennis Hess (Committee Member), Dr. Hang Lu (Committee Member), Dr. Marcus Weck (Committee Member), Dr. Pradeep Agrawal (Committee Member).
Subjects/Keywords: Immobilized catalyst; Hydrolytic kinetic resolution; Vanadium; Oxidative kinetic resolution; Cyclic carbonate; SBA-15; Salen; Silica; Catalysts; Catalysis; Schiff bases
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APA ·
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APA (6th Edition):
Shiels, R. A. (2008). Synthesis, characterization, and evaluation of silica and polymer supported catalysts for the production of fine chemicals. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/29629
Chicago Manual of Style (16th Edition):
Shiels, Rebecca Anne. “Synthesis, characterization, and evaluation of silica and polymer supported catalysts for the production of fine chemicals.” 2008. Doctoral Dissertation, Georgia Tech. Accessed January 23, 2021.
http://hdl.handle.net/1853/29629.
MLA Handbook (7th Edition):
Shiels, Rebecca Anne. “Synthesis, characterization, and evaluation of silica and polymer supported catalysts for the production of fine chemicals.” 2008. Web. 23 Jan 2021.
Vancouver:
Shiels RA. Synthesis, characterization, and evaluation of silica and polymer supported catalysts for the production of fine chemicals. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/1853/29629.
Council of Science Editors:
Shiels RA. Synthesis, characterization, and evaluation of silica and polymer supported catalysts for the production of fine chemicals. [Doctoral Dissertation]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/29629
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