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.