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Chemistry

Oxidation

University of Nebraska - Lincoln

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Full-Text Articles in Physical Sciences and Mathematics

Ligand Fluorination To Optimize Preferential Oxidation Of Carbon Monoxide By Water-Soluble Rhodium Porphyrins, Justin C. Biffinger, Shriharsha Uppaluri, Haoran Sun, Stephen G. Dimagno Jan 2011

Ligand Fluorination To Optimize Preferential Oxidation Of Carbon Monoxide By Water-Soluble Rhodium Porphyrins, Justin C. Biffinger, Shriharsha Uppaluri, Haoran Sun, Stephen G. Dimagno

Stephen DiMagno Papers

Catalytic, low temperature preferential oxidation (PROX) of carbon monoxide by aqueous [5,10,15,20-tetrakis- (4-sulfonatophenyl)-2,3,7,8,12,13,17,18-octafluoroporphyrinato]- rhodium(III) tetrasodium salt, (1[Rh(III)]) and [5,10,15, 20-tetrakis(3-sulfonato-2,6-difluorophenyl)-2,3,7,8,12,13, 17,18-octafluoroporphyrinato]rhodium(III) tetrasodium salt, (2[Rh(III)]) is reported. The PROX reaction occurs at ambient temperature in buffered (4 ≤ pH ≤ 13) aqueous solutions. Fluorination on the porphyrin periphery is shown to increase the CO PROX reaction rate, shift the metal centered redox potentials, and acidify ligated water molecules. Most importantly, β-fluorination increases the acidity of the rhodium hydride complex (pKa = 2.2 ± 0.2 for 2[Rh-D]); the dramatically increased acidity of the Rh(III) hydride complex precludes proton reduction …


Characteristics And Stability Of Oxide Films On Plutonium Surfaces, Harry Guillermo García Flores Dec 2010

Characteristics And Stability Of Oxide Films On Plutonium Surfaces, Harry Guillermo García Flores

Department of Chemistry: Dissertations, Theses, and Student Research

The oxidation of plutonium (Pu) metal continues to be an area of considerable activity. The reaction characteristics have significant implications for production use, storage, and disposition of this radiological material. Developing an accurate physical model of the structures, oxidation states, and oxygen concentration gradients present during oxidation are essential to understanding this process. Traditionally, the stable oxides of Pu have been thought to be plutonium sesquioxide (Pu2O3, O/Pu = 1.5, Pu3+) and plutonium dioxide (PuO2, O/Pu = 2.0, Pu4+), existing in a layered structure on Pu metal. Many of the …