Theoretical kinetic study of the reaction of 2,5-Dihydrofuran with ozone: Mechanism and atmospheric fate of reaction products

VALENTIN, VILLARREAL; MARIA EUGENIA TUCCERI; BRACCO, L.B.

Workshop; Workshop in Computational Chemistry and Molecular Spectroscopy; 2023

The 2,5-dihydrofuran (2,5-DHF) is an unsaturated heterocyclic molecule used as additive to diesel engines and is employed as a component of second generation biofuels [1]. Therefore, the production and use of this compound could increase its concentration in the troposphere. One of the main loss processes in the atmosphere for unsaturated compounds is the reaction with tropospheric ozone. This reaction can be described by the Criegee mechanism where very reactive birradical species, called Criegee Intermediates (CIs), are formed [2]. They can undergo unimolecular reactions or react with atmospheric species to produce different compounds, some of which could be aerosol precursors, affecting quality of air and contributing to climate change. The two reported experimental rate coefficients of the studied reaction are in good agreement with a value of (1.65±0.31) x 10-17cm3 molecule-1s-1 at 298 K and 1 atm [3,4]. Additionally, an investigation based in matrix isolation technique proposes an alternative pathway to the Criegee mechanism, with the formation of complex furan--H2O3 through a dehydrogenation process [5].In order to analyse the potential atmospheric competition between both processes, we present a theoretical investigation of the energetics and kinetics of the reaction of 2,5-DHF with O3. The functional M08-HX/6-311++g(3df,3pd) was used to characterise the species and higher levels of theory, like CCSD(T)/aug-cc-pVTZ and DLPNO CCSD(T)/aug-cc-pVTZ, were employed for a reliable estimation of electronic energy. The rate coefficients were derived applying the canonical transition state theory. The results are in excellent agreement with the experimental values, being of 1.74x10-17cm3 molecule-1s-1 at the DLPNO CCSD(T)/aug-cc-pVTZ//M08-HX/6-311++g(3df,3pd) level of theory. The present results suggest that the Criegee mechanism is dominant in tropospheric conditions. In addition, the kinetics of possible unimolecular processes of the generated CI were investigated, and the reaction between CI and H2O was analysed.[1] L.S. Tran, B. Sirjean, P.A. Glaude, R. Fournet, F. Battin-Leclerc, Energy, 2012, 43, 4-18. [2] L. Vereecken, A. Novelli, A. Kiendler-Scharr, A. Wahner, Phys. Chem. Chem. Phys., 2022, 24, 6428-6443.[3] H.D. Alwe, M.P. Walavalkar, A. Sharma, S. Dhanya, P.D Naik, Atmos. Environ, 2013, 82, 113-120. [4] S.A. Adeniji, J.A. Kerr, M.R. Williams, Int. J. Chem. Kinet.,1981, 13, 209-217.[5] S. Tang, L. Du, N. T. Tsona, H. Zhao, W. Wang, Atmos. Environ, 2017, 162, 23-30.