A computational study of the ozonolysis of sabinene
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The ozonolysis of sabinene has been computationally studied at multiple levels of theory. The reaction proceeds through the so-called Criegee mechanism via the formation of a primary ozonide with two different conformations that dissociate into non-interconvertible zwitterionic Criegee intermediate (syn and anti) conformers and a carbonyl compound. The results show that the decomposition of the Criegee intermediate proceeds through different dissociation pathways. Possible pathways involve the formation of a vinyl hydroperoxide or a dioxirane ester. An alternative novel pathway that does not involve Criegee intermediate formation, but rather epoxide formation, is also investigated. The dissociation of the anti-Criegee intermediate to sabina ketone and OH radicals via the vinyl hydroperoxide pathway is more favorable than the analogous syn-Criegee intermediate dissociation. The calculations show that, between the two competing channels (the ester and vinyl hydroperoxide pathways), the ester pathway is more probable, particularly from the syn-Criegee intermediate. Furthermore, the reactions have been studied in the presence of H2O as a spectator molecule. Interestingly, it had a negligible effect on the energy barrier of the syn-ozone addition as it stabilized all the stationary points. All reactions were found to be strongly exothermic, except in the case of the dissociation of the syn-Criegee intermediate through the vinyl hydroperoxide pathway, where the reaction is endothermic.
KeywordsCriegee intermediate Epoxide Ozonolysis Primary ozonide Sabinene Vinyl hydroperoxide
Almatarneh is grateful to the Deanship of Academic Research at the University of Jordan for the grant (Grant Number: 37/2014-2015). The authors also gratefully acknowledge the Atlantic Computational Excellence Network (ACENET) and Compute Canada for the computer time.
- 14.Pankow JF, Seinfeld JH, Asher WE, Erdakos GB (2001) Modeling the formation of secondary organic aerosol. 1. Application of theoretical principles to measurements obtained in the α-pinene/, β-pinene/, sabinene/, Δ3-carene/, and cyclohexene/ozone systems. Environ Sci Technol 35:1164–1172CrossRefGoogle Scholar
- 37.Frisch MJ, Trucks GW, Schlegel HB, et al (2009) Gaussian 09, Revision A.02. Gaussian, Inc, WallingfordGoogle Scholar
- 40.Zhao Y, Truhlar DG (2008) The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06-class functionals and 12 other function. Theor Chem Acc 120:215–241CrossRefGoogle Scholar
- 50.Almatarneh MH, Elayan IA, Abu‐Saleh AAA, Altarawneh M, Ariya PA (2018) The gas-phase ozonolysis reaction of methylbutenol: A mechanistic study. Int J Quantum Chem. https://doi-org.uml.idm.oclc.org/10.1002/qua.25888