THE OZONOLYSIS OF TETRAMETHYLETHYLENE - CONCENTRATION AND TEMPERATURE EFFECTS

The products of the ozonolysis of tetramethylethylene in hexane or methylene chloride are remarkably dependent on the concentration of tetramethylethylene. Ozonolysis in neat tetramethylethylene gives mostly tetramethylethylene epoxide as product. As the concentration of tetramethylethylene is reduced, more acetone diperoxide is formed until it becomes the major product. The reaction also produces 3-hydroperoxy-2,3-dimethyl-1-butene. The product distribution is also quite dependent on reaction temperature. At a given concentration of the alkene the epoxide yield decreases as the temperature is lowered. Simultaneously the acetone diperoxide yield increases with lower temperature. The results are explained by postulating that energy-rich acetone oxide can be partially converted to dimethyldioxirane which is primarily responsible for the epoxidation. The proposed reaction scheme also has acetone oxide dimerize in a stepwise manner to give an intermediate which can either close to give diperoxide or lose singlet oxygen. The singlet oxygen would then react with tetramethylethylene to give the hydroperoxide.