Browsing by Subject "chemistry"
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Item 4- Tris(1H-Pyrazol-1-Yl)Methyl Phenol(2011-11) Chen, Xiao-Yan; Yang, Xiaoping; Holliday, Bradley J.; Chen, Xiao-Yan; Yang, Xiaoping; Holliday, Bradley J.The title compound, C16H14N6O, was prepared by the condensation of 4-(trifluoromethyl) phenol and sodium pyrazol-1-ide in a yield of 58%. The dihedral angles formed by the planes of the pyrazole rings are 50.7 (2), 71.2 (3) and 95.8 (2)degrees. The molecules are associated into dimers by pairs of intermolecular O-H center dot center dot center dot N hydrogen bonds involving the hydroxy groups and pyrazole N atoms. In addition, pi-pi stacking between the phenol rings of these inversion-related dimers is observed, with a ring centroid-to-centroid distance of 3.9247 (10) angstrom.Item A Survey: Destruction of Chemical Agent Simulants in Supercritical Water Oxidadtion(University of Texas at Austin, 1992-10) Blank, M.R.; Gloyna, E.F.Item Assessment of Ozone Initiated Chemistry in Portable Classrooms(2018-05) Carlson, Jeffrey Andrew; Corsi, RichardA model was developed to predict concentrations of homogeneous and heterogeneous ozone initiated reaction by-products in portable classrooms. The resulting estimates offer reference values for highly occupied indoor environments. Indoor concentrations of formaldehyde (HCHO), 4-oxopentanal (4-OPA), 6-methyl-5-hepten-2-one (6-MHO), and secondary organic aerosols (SOA) were predicted based on various parameters of specific portable classrooms in central Texas. The results were not significant to raise concern for formaldehyde, but they did yield relatively high average and maximum concentrations of 4-OPA, 6-MHO, and SOA. While the health implications of SOA are more well known, less has been done to determine the toxicological effects of 4-OPA and 6-MHO. The results of this report indicate that more research should be conducted to further understand the effects of these compounds on the indoor environment, as well as human health.Item Building a hybrid modular polyketide synthase to investigate ketosynthase selectivity(2023) Annaswamy, Shreyas; Keatinge-Clay, AdrianPolyketides are a diverse class of molecules which are biosynthesized in many different organisms, such as bacteria, fungi, plants, and animals. They are biologically active compounds and are often harnessed for pharmacological purposes. These natural products are synthesized by large enzyme complexes called polyketide synthases (PKSs), which are comprised of various domains, such as the acyltransferase (AT) and ketosynthase (KS), that each perform a specific chemical modification to build and process the polyketide. Type 1 modular PKSs in particular are organized into several modules, each containing different sets of domains, which act in an assembly line fashion to add extender units to a starter unit, shuttling the intermediates between the modules with the help of the acyl carrier protein (ACP). Upon reaching the final module, the product either cyclizes or dissociates for further processing (such as glycosylation).Item The c2d Spitzer Spectroscopic Survey Of Ices Around Low-Mass Young Stellar Objects. III. CH4(2008-05) Oberg, Karin I.; Boogert, Adwin C. A.; Pontoppidan, Klaus M.; Blake, Geoffrey A.; Evans, Neal J.; Lahuis, Fred; van Dishoeck, Ewine F.; Evans, Neal J.CH4 is proposed to be the starting point of a rich organic chemistry. Solid CH4 abundances have previously been determined mostly toward high-mass star-forming regions. Spitzer IRS now provides a unique opportunity to probe solid CH4 toward low-mass star-forming regions as well. Infrared spectra from the Spitzer Space Telescope are presented to determine the solid CH4 abundance toward a large sample of low-mass young stellar objects. A total of 25 out of 52 ice sources in the "Cores to Disks'' (c2d) Legacy program have an absorption feature at 7.7 mu m, attributed to the bending mode of solid CH4. The solid CH4/H2O abundances are 2%-8%, except for three sources with abundances as high as 11%-13%. The latter sources have relatively large uncertainties due to small total ice column densities. Toward sources with H2O column densities above 2 x 10(18) cm(-2), the CH4 abundances (20 out of 25) are nearly constant at 4.7% +/- 1.6%. Correlation plots with solid H2O, CH3OH, CO2, and CO column densities and abundances relative to H2O reveal a closer relationship of solid CH4 with CO2 and H2O than with solid CO and CH3OH. The inferred solid CH4 abundances are consistent with models where CH4 is formed through sequential hydrogenation of C on grain surfaces. Finally, the equal or higher abundances toward low-mass young stellar objects compared with high-mass objects and the correlation studies support this formation pathway as well, but not the two competing theories: formation from CH3OH and formation in gas phase with subsequent freezeout.Item Chemical Compositions, Fall 1995(University of Texas at Austin, Department of Chemistry, 1995) Department of ChemistryItem Chemical Compositions, Fall 1996(University of Texas at Austin, Department of Chemistry, 1996) Department of ChemistryItem Chemical Compositions, Fall 1997(University of Texas at Austin, Department of Chemistry, 1997) Department of ChemistryItem Chemical Compositions, Fall 1998(University of Texas at Austin, Department of Chemistry, 1998) Department of ChemistryItem Chemical Compositions, Fall 1999(University of Texas at Austin, Department of Chemistry, 1999) Department of ChemistryItem Chemical Compositions, Fall 2000(University of Texas at Austin, Department of Chemistry, 2000) Department of ChemistryItem Chemical Compositions, Fall 2001(University of Texas at Austin, Department of Chemistry, 2001) Department of ChemistryItem Chemical Compositions, Fall 2005(University of Texas at Austin, Department of Chemistry, 2005) Department of ChemistryItem Chemical Compositions, Fall 2007(University of Texas at Austin, Department of Chemistry, 2007) Department of ChemistryItem Chemical Compositions, Fall 2008(University of Texas at Austin, Department of Chemistry, 2008) Department of ChemistryItem Chemical Compositions, Fall 2011(University of Texas at Austin, Department of Chemistry, 2011) Department of ChemistryItem Chemical Compositions, Fall 2013(University of Texas at Austin, Department of Chemistry, 2013) Department of ChemistryItem Chemical Compositions, Fall 2014(University of Texas at Austin, Department of Chemistry, 2014) Department of ChemistryItem Chemical Compositions, Fall 2015(University of Texas at Austin, Department of Chemistry, 2015) Department of ChemistryItem Chemical Compositions, Fall/Winter 2003(University of Texas at Austin, Department of Chemistry, 2003) Department of Chemistry