Morning Posters
Aromatic Boronic Acids as Flame Retardants for Polyurethane Foams: Design and Synthesis Chemistry Graduate Research Advisor(s) - Vladimir A Benin, Alexander B Morgan Student(s) - Sravanthi Durganala
9:00 AM-10:30 AM Kennedy Union - Ballroom
We have prepared new terephthalic acids with one or two boronic acid groups, designed as monomers/additives with flame-retardant properties. The syntheses can be accomplished following one of two routes: 1) Via the preparation and use of Grignard reagents or, 2) Via transition metalcatalyzed coupling reactions. A key intermediate compound within the second route, dimethyl 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) terephthalate, was studied in detail, using X-ray structural analysis. Initial flame retardant studies show that both structures have the potential to be effective flame retardants, as evidenced by pyrolysis combustion flow calorimetry (PCFC) studies.
Conductivity of Amphiphile Solutions at Less Than Critical Micelle Concentrations Chemistry Independent Research, Undergraduate Advisor(s) - Robert G Keil Student(s) - Michael W Manhart
9:00 AM-10:30 AM Kennedy Union - Ballroom
The self-assembly of amphiphiles in aqueous solution to form micelles is well-known. The focus of our research was to investigate the aggregate structures formed within aqueous solutions at concentrations well below those required to form micelles, perhaps at concentrations where the onset of lipid raft formation commences. We limited our study to a concentration range from 0.10-1.7mM, sufficiently dilute so that strong electrolyte theory would apply and still sufficiently concentrated so that surface excess concentrations would be negligible. We used solution conductivity as a physical indicator of solution structural changes. We will report the results of these solution conductivity studies. Our results show that aggregates of amphiphiles form at concentrations as small as 0.1mM. Interpretations of Kohlrausch plots suggest polyanions are formed at these most dilute concentrations. The conductivity studies lead to the conclusion that the charge of the polyanion is dependent upon temperature, concentration, and the aliphatic chain length of the amphiphile. From the results, solution structures will be proposed. The conductance data will be discussed in terms of Debye-Huckel-Onsager theory.
Photochemical Degradation of b-Carotene in Carbon Tetrachloride and Hexane: Kinetics and Identification of Reaction Products Chemistry Graduate Research Advisor(s) - David W Johnson, Mark B Masthay Student(s) - Yuan Zhao
9:00 AM-10:30 AM Kennedy Union - Ballroom
The kinetics of photochemical reactions of β-carotene was studied in hexane, carbon tetrachloride and percentages of carbon tetrachloride in hexane below 5%. At low percentages of carbon tetrachloride, the reaction is first order in both carbon tetrachloride and β-carotene. The activation energy of the reactions at temperatures around 25oC was found to be positive but very small. The kinetics from photochemical experiments using UV irradiation are compared with similar experiments conducted with two-photon laser irradiation. The photochemical results are also compared with thermal degradation experiments conducted at temperatures between 250 and 350oC.In addition to the kinetic results, some products of the reaction have been identified by nuclear magnetic resonance spectroscopy. It is interesting to note that under thermal conditions, retinal and retinol are identified as products. Under UV irradiation, there are no identifiable products that contain double bonds.
Physical interactions between PriA and PriB drive DNA replication restart in Neisseria gonorrhoeae Chemistry Graduate Research
9:00 AM-10:30 AM Kennedy Union - Ballroom 41