The gas‐phase ozonolysis reaction of methylbutenol: A mechanistic study. Issue 10 (21st December 2018)

• Record Type: Journal Article
• Authors: Almatarneh, Mansour H.; Elayan, Ismael A.; Abu‐Saleh, Abd Al‐Aziz A.; Altarawneh, Mohammednoor; Ariya, Parisa A.
• Is Part Of: International journal of quantum chemistry. Volume 119:Issue 10(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-12-21
• Subjects: Criegee intermediate -- epoxide -- methylbutenol -- ozonolysis -- volatile organic compounds; Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.25888
• Languages: English
• ISSNs: 0020-7608

Abstract

Abstract: The gas‐phase ozonolysis reaction of methylbutenol through the Criegee mechanism is investigated. The initial reaction leads to a primary ozonide (POZ) formation with barriers in the range of 10–28 kJ mol −1 . The formation of 2‐hydroxy‐2‐methyl‐propanal (HMP) and formaldehyde‐oxide is more favorable, by 10 kJ mol −1, than the syn ‐CI and formaldehyde. The unimolecular dissociation of the more stable syn ‐CI via 1, 5‐H transfer into an epoxide is more favored than the epoxide and 3 O2 formation. The ester channel led to the formation of the acetone and formic acid favorably from the anti ‐CI. The hydration of the anti ‐CI with H2 O and (H2 O)2 is significantly barrierless with a higher plausibility to the latter, and thus they may lead to the formation of peroxides and ultimately OH radicals, as well as airborne particulate matter. Reaction of anti ‐CI with water dimers enhances its atmospheric reactivity by a factor of 28 in reference to water monomers. Abstract : The ozonolysis of methylbutenol has been computationally studied using density functional theory and composite methods. The calculation shows that ozonolysis through a syn ‐ and anti‐ orientation differs by no more than 2 kJ mol −1 . Hydration reactions, secondary ozonide, and ester pathways are included in the model. Novels pathways for the epoxide + 3 O2 and epoxide formation through dissociation and proton transfer, respectively, have been found and kinetically investigated.