Physical Sciences and Mathematics | Open Access Articles

Oxidation Of Phenolic Aldehydes By Ozone And Hydroxyl Radicals At The Air-Water Interface, Md Sohel Rana, Marcelo I. Guzman

Chemistry Faculty Publications

Biomass burning releases highly reactive methoxyphenols into the atmosphere, which can undergo heterogeneous oxidation and act as precursors for secondary organic aerosol (SOA) formation. Understanding the reactivity of such methoxyphenols at the air–water interface is a matter of major atmospheric interest. Online electrospray ionization mass spectrometry (OESI-MS) is used here to study the oxidation of two methoxyphenols among three phenolic aldehydes, 4-hydroxybenzaldehyde, vanillin, and syringaldehyde, on the surface of water. The OESI-MS results together with cyclic voltammetry measurements at variable pH are integrated into a mechanism describing the heterogeneous oxidative processing of methoxyphenols by gaseous ozone (O₃) and …

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An Overview Of Dynamic Heterogeneous Oxidations In The Troposphere, Elizabeth A. Pillar-Little, Marcelo I. Guzman

Chemistry Faculty Publications

Due to the adverse effect of atmospheric aerosols on public health and their ability to affect climate, extensive research has been undertaken in recent decades to understand their sources and sinks, as well as to study their physical and chemical properties. Atmospheric aerosols are important players in the Earth’s radiative budget, affecting incoming and outgoing solar radiation through absorption and scattering by direct and indirect means. While the cooling properties of pure inorganic aerosols are relatively well understood, the impact of organic aerosols on the radiative budget is unclear. Additionally, organic aerosols are transformed through chemical reactions during atmospheric transport. …

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Oxidation Of Benzylic Alcohols And Lignin Model Compounds With Layered Double Hydroxide Catalysts, Justin K. Mobley, John A. Jennings, Tonya Morgan, Axel Kiefer, Mark Crocker

Chemistry Faculty Publications

Alcohol oxidation to carbonyl compounds is one of the most commonly used reactions in synthetic chemistry. Herein, we report the use of base metal layered double hydroxide (LDH) catalysts for the oxidation of benzylic alcohols in polar solvents. These catalysts are ideal reagents for alcohol oxidations due to their ease of synthesis, tunability, and ease of separation from the reaction medium. LDHs synthesized in this study were fully characterized by means of X-ray diffraction, NH₃-temperature programmed desorption (TPD), pulsed CO₂ chemisorption, N₂ physisorption, electron microscopy, and elemental analysis. LDHs were found to effectively oxidize benzylic alcohols …

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A Multi-Size Study Of Gold Nanoparticle Degradation And Reformation In Ceramic Glazes, Nathan Nl. Dinh, Luke T. Dipasquale, Michael C. Leopold, Ryan H. Coppage

Chemistry Faculty Publications

Most traditional ceramic glazes employ high amounts of transition metal colorants that are toxic to the environment and can cause health issues in humans through surface leaching. Gold nanoparticles (Au-NPs) have been found to be environmentally friendly and non-toxic alternative metal colorant in ceramic glazes. The plasmon band observed with Au-NPs can result in vibrant solutions by manipulating NP size, shape, and concentration; however, the effects of traditional firing in both reductive and oxidative kilns on Au-NPs are poorly understood. Aside from ancient art processes whose mechanisms have not been fully explored, the use of Au-NPs as suspended ceramic glaze …

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Nitrate Radicals And Biogenic Volatile Organic Compounds: Oxidation, Mechanisms And Organic Aerosol, Nga Lee Ng, Steven S. Brown, Alexander T. Archibald, Elliot Atlas, Ronald C. Cohen, John N. Crowley, Douglas A. Day, Neil M. Donahue, Juliane L. Fry, Hendrik Fuchs, Robert J. Griffin, Marcelo I. Guzman, Hartmut Hermann, Alma Hodzic, Yoshiteru Iinuma, José L. Jimenez, Astrid Kiendler-Scharr, Ben H. Lee, Deborah J. Luecken, Jingqiu Mao, Robert Mclaren, Anke Mutzel, Hans D. Osthoff, Bin Ouyang, Benedicte Picquet-Varrault, Ulrich Platt, Havala O. T. Pye, Yinon Rudich, Rebecca H. Schwantes, Manabu Shiraiwa, Jochen Stutz, Joel A. Thornton, Andreas Tilgner, Brent J. Williams, Rahul A. Zaveri

Chemistry Faculty Publications

Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO₃) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than 3 decades, during which time a large body of research has emerged from laboratory, field, and modeling studies. NO₃-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone, and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number …

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Electronic Effects In Oxidation Reactions Utilizing Dinuclear Copper Complexes With The Bis[3-(2-Hydroxybenzylideneamino)Phenyl] Sulfone Ligand, Armando M. Guidote Jr, Ronald L. Reyes, Riyo Kashihara, Yasuhiko Kurusu, Yoshihiro Masuyama

Chemistry Faculty Publications

Copper acetate and the ligands bis[3-(3-tert-butyl-2-hydroxy-5-methoxybenzylideneamino)phenyl] sulfone and bis[3-(3,5-di-tert-butyl-2-hydroxybenzylideneamino)phenyl] sulfone were reacted to form the complexes with 2:1 copper:ligand ratio, Cu2[B(t-Bu) (OMe)BAPS](µ-OCH3)2 (4) and with 2:2 copper:ligand ratio, Cu2[B(t-Bu)2BAPS]2 (5), respectively. Structures of 4 and 5 were determined based on IR, UV-Vis, and FAB-MS data in comparison with previously characterized related copper complexes. The two complexes 4 and 5 were utilized in the oxidation of the substrates 2,4- and 2,6-di-tertbutylphenol (dtbp) at -50C with H2O2 in CH2Cl2. The coupling products are preferred in both cases. For 2,4-dtbp, yields of 4,600% and 7,200% of 3,3’,5,5’-tetra-tert-butyl-2,2’- biphenol were achieved with the use …

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Physico-Chemical And Microbiological Parameters In The Deterioration Of Virgin Coconut Oil, Ian Ken D. Dimzon, Melodina F. Valde, Jaclyn Elizabeth R. Santos, Mark Joseph Garrovillas, Henson M. Dejarme, Jo Margarette W. Remollo, Fabian M. Dayrit

Chemistry Faculty Publications

The deterioration of virgin coconut oil (VCO) due to physico-chemical oxidation and hydrolysis and microbiological processes was studied. The physico-chemical oxidation of VCO in the air at room temperature was negligible. Oxidation of VCO was observed only in the presence of air, UV radiation, ferric ion (Fe3+), and high free fatty acid (FFA) content. Chemical hydrolysis was performed at varying moisture levels and temperatures. The rate of hydrolysis to produce FFAs was measured using 31P NMR under conditions of saturated water (0.22%) and 80°C was found to be 0.066 µmol/g-hr (expressed as lauric acid). At 0.084% moisture and 80°C, the …

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Particle Growth In Urban And Industrial Plumes In Texas, Charles A. Brock, Michael Trainer, Thomas B. Ryerson, J. Andrew Neuman, David D. Parrish, John S. Holloway, Dennis K. Nicks, Gregory J. Frost, Gerhard Hübler, Fred C. Fehsenfeld, J. Charles Wilson, J. Michael Reeves, Bernard G. Lafleur, Henrike Hilbert, Elliot L. Atlas, Stephen G. Donnelly Ph.D., Sue M. Schauffler, Verity R. Stroud, Christine Wiedinmyer

Chemistry Faculty Publications

Particle size distributions and gas-phase particle precursors and tracer species were measured aboard an aircraft in the plumes downwind from industrial and urban sources in the vicinity of Houston, TX during the daytime in late August and early September 2000. Plumes originating from the Parish gas-fired and coal-fired power plant, petrochemical industries along the Houston ship channel, the petrochemical facilities near the Gulf coast, and the urban center of Houston were studied. Most of the particle mass flux advected downwind of Houston came from the industries and electrical utilities at the periphery of the city rather than from sources in …

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Full-Text Articles in Physical Sciences and Mathematics

Oxidation Of Phenolic Aldehydes By Ozone And Hydroxyl Radicals At The Air-Water Interface, Md Sohel Rana, Marcelo I. Guzman

Chemistry Faculty Publications

An Overview Of Dynamic Heterogeneous Oxidations In The Troposphere, Elizabeth A. Pillar-Little, Marcelo I. Guzman

Chemistry Faculty Publications

Oxidation Of Benzylic Alcohols And Lignin Model Compounds With Layered Double Hydroxide Catalysts, Justin K. Mobley, John A. Jennings, Tonya Morgan, Axel Kiefer, Mark Crocker

Chemistry Faculty Publications

A Multi-Size Study Of Gold Nanoparticle Degradation And Reformation In Ceramic Glazes, Nathan Nl. Dinh, Luke T. Dipasquale, Michael C. Leopold, Ryan H. Coppage

Chemistry Faculty Publications

Chemistry Faculty Publications

Electronic Effects In Oxidation Reactions Utilizing Dinuclear Copper Complexes With The Bis[3-(2-Hydroxybenzylideneamino)Phenyl] Sulfone Ligand, Armando M. Guidote Jr, Ronald L. Reyes, Riyo Kashihara, Yasuhiko Kurusu, Yoshihiro Masuyama

Chemistry Faculty Publications

Physico-Chemical And Microbiological Parameters In The Deterioration Of Virgin Coconut Oil, Ian Ken D. Dimzon, Melodina F. Valde, Jaclyn Elizabeth R. Santos, Mark Joseph Garrovillas, Henson M. Dejarme, Jo Margarette W. Remollo, Fabian M. Dayrit

Chemistry Faculty Publications

Chemistry Faculty Publications