Thermolysis reaction of 3,6-dibutanal-1,2,4,5-tetroxane

A. N. PILA; N.L. JORGE; A. G. BORDÓN; J. M. ROMERO; A. HERNÁNDEZ LAGUNA; M.I. PROFETA; ANDRÉ GRAND

SANTIAGO DE CHILE

Congreso; XLIV CONGRESO INTERNACIONAL DE QUÍMICOS TEÓRICOS DE EXPRESIÓN LATINA (QUITEL 2018); 2018

Centro de Extensión UC Pontificia Uiversidad Catolica de Chile

In this work, thermolysis reaction of the 3,6-dibutanal-1,2,4,5-tetroxane (DBT) is computationally investigated in positions axial-axial. Critical points (CP) at the singlet and triplet Potential Energy Surfaces (PES) were performed by DFT calculations at BHANDHLYP/6-311G** level. Spin-orbit coupling and crossing points between both surfaces were determined at CASSCF level. In a first step, one of the peroxyde bonds is breakdown, producing a diradical open structure (o), and, after a stepwise mechanism, two glutaraldehyde molecules and molecular oxygen, as final products, are obtained. Reaction starts at the singlet PES, and o is reached. Due to a spin-orbit coupling between o of the singlet and triplet PES, a crossing point is found and the system goes from the singlet to the triplet PES, and the next steps go on the triplet state reaction path, which turns out to be an exothermic reaction. An analysis of the total reaction showed that the initial C?O bond cleavage of o was the rate-limiting step. The activation energies of the rate-limiting step of the reaction are 16.81 kcal/mol, which is lower than the tetroxane rate-limiting step (26,9 kcal / mol, [1]); therefore, DBT could turn out to be a much more explosive compound than the tetroxane.References:[1] N. L. Jorge, J. M. Romero, A. Grand, and A. Hernández-Laguna, Chemical Physics 393 (2012) 37.