Theoretical investigation on the reaction mechanism of CF₃OCHF₂ + O(¹D)

Abstract

The reaction mechanism of the multi-channel reaction of CF₃OCHF₂ + O(¹D) has been investigated theoretically. Three possible initial association ways are found, i.e. O(¹D) insertion into the C–H bond to form energy-rich intermediates a(a₁ –a₄ ) CF₃OCF₂OH, O(¹D) insertion into the C–O bond to form energy-rich intermediate b CF₃OOCHF₂, O(¹D) addition to the F atom to generate intermediates c CHF₂OCF₃O and c₁ CF₃OCFHOF. The geometries are optimized at the B3LYP/6-311G(d, p) level, and the energy profiles are further refined by MC-QCISD level of theory. The mechanism can generally be described as association, isomerization, and dissociation. There are five energetically accessible reaction pathways. Eight products are located on potential energy surfaces (PESs). It is predicted that the main products are P2 (F₂CO + CF₃OH), P3 (2F₂CO + HF), and P4 (CF₃OCFO + HF), while P1 (CF₂O(O)CF₃ + H) and P5 (CF₃O + CF₂HO) are minor products. Furthermore, to further reveal the thermodynamic properties, the enthalpies of formation of CF₃OCHF₂ are evaluated via isodesmic reactions at the MC-QCISD//B3LYP/6-311G(d, p) level and the reaction enthalpies of the major reaction channels are calculated at the same level.

Keywords:

• reaction mechanism
• CF₃OCHF₂ + O(¹D)
• potential energy surfaces (PESs)
• transition state

Acknowledgements

This work is supported by the Training Fund of NENU'S Scientific Innovation Project (NENU-STC07016). We are greatly thankful for the referees’ helpful comments.