Synthesis of trifluoronitromethane, CF₃NO₂: photochemical scale-up and a new thermogeneration method with a refined purification technique

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dc.contributor Arduengo, Anthony J.
dc.contributor Shaughnessy, Kevin H.
dc.contributor Vincent, John B.
dc.contributor O'Brien, Brian A.
dc.contributor.advisor Thrasher, Joseph S. Hauptfleisch, John O. 2017-02-28T22:23:11Z 2017-02-28T22:23:11Z 2009
dc.identifier.other u0015_0000001_0000188
dc.identifier.other Hauptfleisch_alatus_0004D_10231
dc.description Electronic Thesis or Dissertation
dc.description.abstract The research herein investigates two primary methods to synthesize trifluoronitromethane, CF₃NO₂. The first method, a photochemical synthesis, was discovered by the Thrasher group and published in 2002. This photochemical method was the first one-step method for generating CF₃NO₂ and uses trifluoroiodomethane, CF₃I, and nitrogen dioxide, NO₂, as the reactants. This process is initiated by a 420 nm blue light apparatus that splits the C-I bond. The optimization and scale-up of this reaction had not been previously investigated. The production of multiple grams of CF₃NO₂ in a single reaction turned out to be impractical due to the equilibrium of 2 NO₂ with N₂O₄. However, the ideal conditions for the maximum generation of CF₃NO₂ were found to be a total pressure of 0.3 atm, a stoichiometric ratio of 1.1 : 1 of NO₂ : CF₃I, a temperature of at least 55 °C, and a reaction time of 18 hours. Even though this method could not be scaled-up, it still represents the fastest and least expensive method for generating lab quantities of 1-3 grams of CF₃NO₂ via multiple reactions. Because of the aforementioned limitations of the photochemical method, a new method for generating larger quantities of CF₃NO₂ had to be discovered. This new method involves the homolysis of the C-I bond in CF₃I at approximately 200 °C in the presence of NO₂ in a pressure vessel. The increase in reaction temperature allows for the previous limitations due to the 2 NO₂ to N₂O₄ equilibrium to be overcome, allowing for larger quantities, 10-100 grams, of CF₃NO₂ to be produced in a single reaction. This method can be carried out over a large pressure range, 10-60 atm; similar reaction times, 18-24 hours; and with a modest increase in the yield to 35-50%. A detailed kinetics study of this new preparative route was carried out by following both the disappearance of CF₃I and the appearance of CF₃NO₂. The results yielded a C-I bond energy for CF₃I that is in agreement with literature values. A new purification method was also developed for the larger quantities of CF₃NO₂, and the thermal properties of CF₃NO₂ were investigated using an accelerating rate calorimetry (ARC). The molecule CF₃NO₂ was found to be stable to almost 300 °C.
dc.format.extent 170 p.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.subject.other Chemistry, Inorganic
dc.title Synthesis of trifluoronitromethane, CF₃NO₂: photochemical scale-up and a new thermogeneration method with a refined purification technique
dc.type thesis
dc.type text University of Alabama. Dept. of Chemistry Chemistry The University of Alabama doctoral Ph.D.

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