The surface reaction in the heterogeneous isotope exchange between sodium iodide and gaseous methyl iodide in the region of small methyl iodide pressures
Description
The heterogeneous isotope exchange of iodine in the system sodium iodide/methyl iodide was investigated at very low methyl iodide pressures, i.e. with a very reduced amount of exchangeable particles in the gas phase. Methyl iodide was labelled with I 131 and pumped in a cycle apparatus in an inert gas stream (Argon) through a reaction cell heated to 177 to 2550C with fine-particled sodium iodide. A change of the mechanism of the surface reaction could be seen with the transfer into the methyl iodide low-pressure region. The desorption is no longer rate-determining, instead it is the change of place of the iodine between the gas molecules and the crystal lattice. The activation energy 6.05 +- 0.51 kcal/mol is clearly lower than that found for the desorption - controlled mechanism (11.8 kcal/mol.) (FW)
Abstract (German)
Der heterogene Isotopenaustausch von Jod im System Natriumjodid/Methyljodid wurde bei sehr niedrigen Methyljodid-Druecken, d.h. bei einem sehr verringerten Angebot an austauschfaehigen Teilchen in der Gasphase, untersucht. Methyljodid wurde mit J-131 markiert und in einer Kreislaufapparatur in einem Inertgasstrom (Argon) durch eine auf 177 bis 2550C geheizte Reaktionszelle mit feinteiligem Natriumjodid gepumpt. Es zeigte sich beim Uebergang in den Bereich niedriger Methyljodiddruecke eine Aenderung des Mechanismus der Oberflaechenreaktion. Nicht mehr die Desorption ist geschwindigkeitsbestimmend, sondern der Platzwechsel des Jodids zwischen den Gasmolekuelen und dem Kristallgitter. Die Aktivierungsenergie ist mit 6,05 +- 0,51 kcal/Mol deutlich niedriger als die fuer den desorptionskontrollierten Mechanismus gefundene (11,8 kcal/Mol). (FW)Additional details
Additional titles
- Original title (German)
- Die Oberflaechenreaktion beim heterogenen Isotopenaustausch zwischen Natriumjodid und gasfoermigem Methyljodid im Bereich kleiner Methyljodid-Druecke
Publishing Information
- Imprint Pagination
- 4 p.
INIS
- Country of Publication
- Germany
- Country of Input or Organization
- Germany
- INIS RN
- 8289390
- Subject category
- S37: INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; S75: CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY;
- Resource subtype / Literary indicator
- Thesis, Non-conventional Literature
- Descriptors DEI
- ADSORPTION; CHEMICAL REACTION KINETICS; CHEMISORPTION; GASES; IODINE 131; ISOTOPIC EXCHANGE; LABELLED COMPOUNDS; METHYL IODIDE; PRESSURE DEPENDENCE; SODIUM IODIDES; SOLIDS; SURFACES
- Descriptors DEC
- ALKALI METAL COMPOUNDS; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; CHEMICAL REACTIONS; DAYS LIVING RADIOISOTOPES; FLUIDS; HALIDES; HALOGEN COMPOUNDS; INORGANIC PHOSPHORS; INTERMEDIATE MASS NUCLEI; IODIDES; IODINE COMPOUNDS; IODINE ISOTOPES; ISOTOPES; KINETICS; NUCLEI; ODD-EVEN NUCLEI; ORGANIC COMPOUNDS; ORGANIC HALOGEN COMPOUNDS; ORGANIC IODINE COMPOUNDS; PHOSPHORS; RADIOACTIVE MATERIALS; RADIOISOTOPES; REACTION KINETICS; SEPARATION PROCESSES; SODIUM COMPOUNDS
Optional Information
- Notes
- 1 ref. Available from the library of the Techn. Hochschule Darmstadt.