Kinetic and mechanism studies of the ozonolysis of three unsaturated ketones


Yunhong Zhang , Weiran Li , Meifang Chen , Yi Chen , Shengrui Tong , Maofa Ge , Yucong Guo , Tao WANG , Jianmin CHEN , Abdelwahid Mellouki , Christian GEORGE , Yujing MU , Hong LI

DOI:10.1016/j.jes.2020.03.031

Received September 14, 2019,Revised , Accepted March 18, 2020, Available online May 01, 2020

Volume 32,2020,Pages 23-32

Reaction rate constants and products of 1-octen-3-one, 3-octen-2-one and 4-hexen-3-one with ozone were studied in a 100-L fluorinated ethylene propylene (FEP) Teflon film bag using absolute rate method at 298 ± 1 K and atmospheric pressure. The rate constants were (1.09 ± 0.12) × 10−17, (3.48 ± 0.36) × 10−17 and (5.70 ± 0.60) × 10−17 cm3/(molecule⋅sec), respectively. According to the obtained rate constants, the effects of carbonyl were discussed. The carbonyl group in β position has a net withdrawing effect with respect to an olefinic bond, then causing the decline of rate constants. The quantum chemical calculation was used to explain the results of rate constants. The products of ozonolysis were mainly aldehydes, which have significant influence on the formation of SOA, and hence play an important role in the atmosphere. In this work, we detected the main products of reaction and proposed the reaction mechanism by combining the results of quantum chemical calculations. Atmospheric lifetime for three unsaturated ketones reacted with ozone was 36.4, 11.4 and 6.9 hr for 1-octen-3-one, 3-octen-2-one and 4-hexen-3-one, respectively.

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