Hydration and Secondary Ozonide of the Criegee Intermediate of Sabinene

Abstract

A computational study of the formation of secondary ozonide (SOZ) from the Criegee intermediates (CIs) of sabinene, including hydration reactions with H 2 O and 2H 2 O, was performed. All of the geometries were optimized at the B3LYP and M06-2X with several basis sets. Further single-point energy calculation at the CCSD(T) was performed. Two major pathways of SOZ formation suggest that it is mainly formed from the sabinene CI and formaldehyde rather than sabina ketone and formaldehyde-oxide. However, in both pathways, the activation energies are within a range of ±5 kJ mol –1 . Furthermore, the hydration reactions of the anti-CI with H 2 O and 2H 2 O showed that the role of the second water molecule is a mediator (catalyst) in this reaction. The dimer hydration reaction has lower activation energies than the monomer by 60 and 69 kJ mol –1 , at the M06-2X/6-31G(d) and CCSD(T)+CF levels of the theory, respectively. A novel water-mediated vinyl hydroperoxide (VHP) channel from both the monomer and dimer has been investigated. The results indicate that the direct nonmediated VHP formation and dissociation is interestingly more possible than the water-mediated VHP. The density functional theory calculations show that the monomer is faster than the dimer by roughly 22 kJ mol –1 . Further, the infrared spectrum of sabina ketone was calculated at B3LYP/6-311+G(2d,p); the calculated carbonyl stretching of 1727 cm –1 is in agreement with the experimental range of 1700–1800 cm –1 .

Kinetics and Condensed-Phase Products in Multiphase Ozonolysis of an Unsaturated Triglyceride

“…35 Specifically, Heine et al 36 and Fooshee et al 37 show SOZs from squalene particles and surfaces, respectively, and other sources include ascorbic acid (Enami et al) 38 and sabinene (Almatarneh et al). 39 In addition, as illustrated by multiphase ozonolysis studies of oleic acid and squalene, products with other functional groups including aldehydes and carboxylic acids are also identified. 35,36 Multiple studies have demonstrated that ozonolysis of oleic acid is relatively efficient, with an ozone uptake coefficient (γ) on the order of 10 −3 , 40−44 whereas squalene has a γ on the order of 10 −4 .…”

“…The formation of SOZs not only arises from triglycerides but also via ozonolysis of numerous unsaturated compounds . Specifically, Heine et al and Fooshee et al show SOZs from squalene particles and surfaces, respectively, and other sources include ascorbic acid (Enami et al) and sabinene (Almatarneh et al) . In addition, as illustrated by multiphase ozonolysis studies of oleic acid and squalene, products with other functional groups including aldehydes and carboxylic acids are also identified. , Multiple studies have demonstrated that ozonolysis of oleic acid is relatively efficient, with an ozone uptake coefficient (γ) on the order of 10 –3 , − whereas squalene has a γ on the order of 10 –4 . , These reactions proceed through the formation of the unstable primary ozonide, which falls apart into biradical Criegee intermediates (CI) and aldehydes with a number of subsequent reactions, ,,− ,, as described later in Scheme .…”

Computational Study of the Dissociation Reactions of Secondary Ozonide

“…The theoretical work by Jørgensen and Gross afforded an insight into the experimental work of Naa and co-workers by surveying plausible, pertinent reaction mechanisms [18]. Moreover, our previous work on ozonolysis reactions provided good initial guesses that helped us attain a complete picture about the proposed mechanisms for this study [7,[19][20][21][22][23].…”

The gas‐phase ozonolysis reaction of methylbutenol: A mechanistic study

“…The quantum calculations using density functional theory (DFT) and composite methods were performed utilizing the Gaussian 09 package . The rate constant of the ozonolysis reaction and it is resulting reactions has been computed using transition state theory (TST) at 298.15 K. The selection of methods and basis sets is based on our previous work on the atmospheric ozonolysis reaction mechanisms of sabinene and phenanthrene . The stationary and saddle points were optimized using the B3LYP method with the split‐valence polarized 6‐31G(d,p) basis set.…”