Date of Award

6-1975

Document Type

Open Access

Degree Name

Bachelor of Science

Department

Chemistry

Language

English

Abstract

There are two theories about the mechanism of the ozone-olefin reaction. One is that ozone makes a one-step four-center attack on the olefin to form a primary ozonide. Another theory is that ozone makes an electrophilic attack of the olefin to form a pi complex. The pi complex then collapses into the primary ozonide. The relative rates of reaction of a series of symmetrical and unsymmetrical olefins were determined. Gas chromatograph was used to measure the relative concentration of the various olefins before and after ozonolysis. The relative rates of ozonolysis were then calculated from the data. It was observed that for olefin with electron-donating substituent groups, the symmetrical olefins have a higher reaction rate than the unsymmetrical isomer. The opposite trend was observed in the olefins with electron-withdrawing substituent groups. From the trend of the relative rates, it suggested that both inductive effect steric effect influence the rate of ozone-olefin reaction. The inductive effect determines the reaction mechanism for the collapse of the pi complex. Steric effect controls the rate of the ring closure step to form the primary ozonide. The two-step mechanism in forming primary ozonide supports the trend of our reaction rate. The one-step mechanism, however, cannot explain this trend. It is concluded that the ozone-olefin reaction goes by a two-step mechanism in which a pi complex rearranges to form the primary ozonide.

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In Copyright - Educational Use Permitted.