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3075223 
Journal Article 
Mechanistic and kinetic study on the ozonolysis of 2,4-hexadienedial 
Zhong, Li; Gao, Ya; Chen, X; Yao, Wei; Li, S 
2014 
1 
Structural Chemistry
ISSN: 1040-0400
EISSN: 1572-9001 
25 
5 
1405-1414 
WOS:000342173200008 
The formation and unimolecular reactions of primary ozonides and carbonyl oxides arising from the O-3-initiated reactions of 2,4-hexadienedial (HDE) have been investigated using the density functional theory and ab initio method. The activation energies of O-3 cycloaddition to the > C=C < and > C=O bonds of HDE for the formation primary ozonides (POZ1 and POZ2) are 4.79 and 21.37 kcal mol(-1), respectively, implying that the initial O-3 to the > C=C < bond is favorable pathway. Cleavage of POZ1 to form carbonyl oxides occurs with a barrier of 12.19-21.35 kcal mol(-1), and the decomposition energies range from -1.09 to -15.75 kcal mol(-1). The CHOCHOO radical, the hydroxyl radical (OH) formation via H-migration is more favorable than the dioxirane formation via rearrangement. However, the CHOCH=CHCHOO radical, the dioxirane formation via rearrangement is more favorable than OH formation. Using the transition state theory, the rate constants of formation of POZ1 and POZ2 are 1.49 x 10(-19) and 6.03 x 10(-25) cm(3) molecule(-1) s(-1) at 300 K, respectively. This study shows that the hyperconjugative effect makes O-3 addition to > C=C < and > C=O bonds of HDE more difficult than to > C=C < bond of ethylene and isoprene and to > C=O bond of formaldehyde. The largest rate constants of OH formation and dioxirane formation in the unimolecular reactions of carbonyl oxides are 6.13 x 10(-4) and 7.93 x 10(-1) s(-1) at 300 K, respectively. The dioxirane is main product in the unimolecular reaction of the carbonyl oxides arising from the O-3-initiated reaction of HDE. 
2,4-Hexadienedial; Ozonolysis mechanism; Primary ozonide; Carbonyl oxide; Ab inito and DFT; Kinetic study