Accession Number : AD0671928

Title :   SURFACE STABILIZED FREE RADICALS.

Descriptive Note : Final rept. 1 May 64-31 Jan 68,

Corporate Author : MANITOBA UNIV WINNIPEG DEPT OF CHEMISTRY

Personal Author(s) : Gesser,H. D.

Report Date : 31 MAY 1968

Pagination or Media Count : 18

Abstract : Methyl radicals, formed by the photolysis of CH3I at 77K were stabilized on the porous glass indefinitely at this temperature and decayed with first order kinetics at higher temperatures with an activation energy of about 2 kcal/mole. The decay showed a cascade effect indicating the presence of a multi site surface. High resolution ESR spectra gave a further splitting of the hyperfine lines which were interpreted in terms of a B11-CH3 interaction. This was subsequently shown to be probably due to water on the surface and the degassing condition since a deuterated surface almost eliminated the effect. Line width measurement for CH3 led to a tumbling frequency which is of the order of 10 to the 8th power/sec and an activation energy for tumbling of about 300 cal/mole for CH3 on the surface. The photolysis of CH3OH (and its deuterated isomers) on porous glass was also examined and interpreted in terms of the I.R. absorption studies. Comparable studies were also made with a TiO2 impregnated surface. The stabilization of hydrogen atoms was also examined and was similar in behaviour to CH3 except that the decay was 2nd order and the H atom showed definite decay at 77K. (Author)

Descriptors :   (*FREE RADICALS, STABILIZATION), HYDROCARBONS, CRYOGENICS, POROUS MATERIALS, GLASS, REACTION KINETICS, HEAT OF ACTIVATION, ELECTRON PARAMAGNETIC RESONANCE, MOLECULAR ASSOCIATION, LINE SPECTRA, HALOGENATED HYDROCARBONS, CARBINOLS, PHOTOLYSIS, DEUTERIUM, TITANIUM COMPOUNDS, DIOXIDES, HYDROGEN, CANADA

Subject Categories : Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE