Theoretical study on the synthesis mechanism of TRAT/TAT from 1,3,5-trioxane and acetonitrile

The synthesis of TRAT/TAT, the nitrification precursor of RDX/HMX, using the small molecule method with 1,3,5-trioxane and acetonitrile, and sulfuric acid as the catalyst, is a popular research topic. However, the mechanism of this reaction is not complete. Therefore, we used the quantum chemical methods, combined with the experimental results, to put forward a reasonable reaction mechanism. The enthalpy changes of the reactions were calculated. The formation of TRAT and TAT was exothermic, which was consistent with the reaction phenomenon. According to the comparison of Gibbs free energy barrier, TRAT was the dominant product, and the process of dehydration and cyclization was the rate-determining step of the formation of TRAT and TAT.