Synthesis and Low Temperature Spectroscopic Observation of 1,3,5-Trioxane-2,4,6-Trione: The Cyclic Trimer of Carbon Dioxide

1,3,5-Trioxane-2,4,6-trione
(cyclic trimer of CO2) is
the product of a four-step synthesis: chlorination of isobutyraldehyde;
cyclotrimerization of 2-chloro-2-methylpropanal; dehydochlorination
of 2,4,6-tris­(2-chloropropan)-2-yl-1,3,5-trioxane; ozonolysis at −80
°C of 2,4,6-tri­(propan-2-ylidene)-1,3,5-trioxane. This trioxane-trione
is detected in solution at temperatures between −80 to −40
°C, and its conversion to CO2 is monitored by 13C NMR and FTIR. The CO2 trimer has a half-life
of approximately 40 min at −40 °C.