Reactions of Free Radicals with Sulphur Dioxide

Research output: ThesisDoctoral Thesis


The addition reactions between sulphur dioxide and methyl, ethyl and trifluoromethyl radicals were studied in a gas-line of conventional design. Product analysis was performed by mass spectrometry and gas chromatography.

Methyl radicals were found to exist in an equilibrium with methylsulphonyl radicals. The equilibrium was found to move to the left as the temperature was raised. A similar equilibrium was found to exist between ethyl and ethylsulphonyl radicals, though the results obtained indicated that ethyl-sulphonyl radicals were slightly less stable than the methyl analogues. No equilibrium was found in the case of trifluoromethylsulphonyl radicals, which appeared to be stable at temperatures of up to 250 °C . Large-scale experiments led to the identification of the sulphone and the disulphone among the products of this system.

The addition reaction between methyl radicals and oxygen was also studied, and the third-order rate constant obtained was found to agree with the results obtained by other workers. Experiments performed on a system containing methyl radicals and a mixture of oxygen and sulphur dioxide, yielded a value for the relative rates of the two addition reactions. Using the value for the rate constant of addition to sulphur dioxide obtained in this work, a reasonable value for the rate constant of addition to oxygen was thus calculated.
Original languageEnglish
Awarding Institution
  • University of Edinburgh
  • Thynne, John C.J., Supervisor, External person
Award date19 Jul 1967
Publication statusPublished - 1967

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