Design and testing of an ozonolysis reactor module with on-the-fly ozone degassing under flow conditions

Abstract

Ozonolysis is an attractive, efficient, and green means of introducing oxygen containing functionalities using only oxygen and electricity. Unfortunately, safety issues associated with the accumulation of dissolved ozone and potentially explosive ozonides coupled with an oxygen rich reaction atmosphere have limited its integration into large scale process reactions. Herein we report on the development and testing of a prototype flow-based ozonolysis reactor which allows on-the-fly removal of ozone and oxygen negating the need for a downstream degassing step and allowing the continuous processing of intermediate ozonides in a safe manner. The approach lends itself to being able to telescope directly into downstream reactions without concern for the effect of residual ozone and minimises contact between the oxygen rich ozone atmosphere and the reaction mixture. The prototype was shown to remove between 98.5 and 99.7% of residual ozone-oxygen on-the-fly and its performance was demonstrated through the ozonolysis of several alkenes to afford a range of oxygen containing functional groups in good to high yields.