The gas kinetics of some thermal reactions of cyclic organosilanes.

The work outlined in this thesis is largely concerned with the gas kinetics of the pyrolyses of four cyclic organosilicon corrpounds. Also described is a study of the reaction between 2-methyl-2-silaprcpene, a reactive Intermediate of considerable current interest [1], and oxygen [2]. This last investigation was undertaken in connection with work on the oxidation of tetramethylsilane [3]. It provided much needed quantitative information on the reactions of silaalkenes. A study of the pyrolysis of 1, 1, 2, 2, 4, 4-hexamethyl-1, 2, 4-trisila- cyclopentane [4] enabled the reaction mechanism of the previously described [5] isomerisation of the same compound to be elucidated. The thermal decamposition of l, l, 3, 3-tetramethyl- l, 3-disilacyclobutane was investigated to provide information regarding the above two studies. The last section of the thesis is concerned with the thermal decomposition of two vinyl-substituted silacyclobutanes. The interest here was in the reactions of the silaalkenes produced: previous work [6, 7] has suggested that both compounds yield silabutadienes which undergo reaction alternative to dimerisation. Another reason for this particular study was to see whether vinyl substitution at silicon enabled the sits of initial ring cleavage to be the silicen-carbon bond (1, 1-dimethyl-l-silacyclobutane decomposition proceeds via carbon- carbon bond rupture).