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Identifier uch.chemistry.msc//2004stefanopoulos
Title Προσδιορισμός κινητικών παραμέτρων και μηχανιστική ανάλυση της αντίδρασης ατόμων χλωρίου Cl με διωμεθάνιο CH2I2 στην αέρια φάση
Creator Stefanopoulos, Vasileios
Abstract The present work focuses on the kinetic study of the reaction between atomic chlorine and diiodomethane in the gas phase. The rate constants were measured at the following temperatures 273, 303, 333, 363Κ, and were measured to be 1.94x10-11, 2.12x10-11, 2.31x10-11, and 2.55x10-11 cm3 molecule-1 s-1, respectively. All kinetic measurements were performed in a Very Low Pressure Reactor (V.L.P.R.) system, using a quadrupole mass analyzer to detect both reactants and products. The mechanism of the reaction includes both the direct abstraction of iodine leading to the formation of the ICl molecule and the CH2I radical, as well as the abstraction of hydrogen leading to the formation of HCl and the CHI2 radical. Even though the total rate constant of the reaction was measured, it was not feasible to estimate their branching ratio. The examination of the primary products of the diiodomethane oxidation in the atmosphere was also attempted by using a three-inlet reaction cell. Molecular oxygen was added in the reacting mixture (Cl and CH2I2) and the products were monitored. The mass spectrometric analysis of the reaction products showed the appearance of the following peaks m/z = 29, m/z = 46, m/z = 44, which correspond to stable products. The first peak is attributed to H2CO, while the others to HCOOH and CO2 respectively. Finally, oxidation experiments were conducted, using fluorine atoms instead of chlorine atoms, because the reaction between fluorine and CH2I2 follows mainly the iodine abstraction pathway. The oxidation products were the same as for the Cl-initiated reaction (H2CO, HCOOH, CO2).
Issue date 2004-07-01
Date available 2004-07-27
Collection   School/Department--School of Sciences and Engineering--Department of Chemistry--Post-graduate theses
  Type of Work--Post-graduate theses
Permanent Link https://elocus.lib.uoc.gr//dlib/f/6/c/metadata-dlib-2004stefanopoulos.tkl Bookmark and Share
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