Issue 6, 2017, Issue in Progress

Kinetics study of heterogeneous reactions of ozone with unsaturated fatty acid single droplets using micro-FTIR spectroscopy

Abstract

Ozone initiated heterogeneous oxidation of micron-sized oleic acid (OA), linoleic acid (LA), and linolenic acid (LOA) single droplets was investigated using a gas-flow system combined with microscopic Fourier transform infrared (micro-FTIR) spectrometer. The pseudo-first-order rate constant (kapp) and the overall uptake coefficient (γ) are obtained by quantitatively estimating the changes in absorbance area of the C[double bond, length as m-dash]O stretching band at 1710 cm−1, which is assigned to the carboxyl group of the reactant. The overall kinetics is dominated by surface reaction. And the effect of surface adsorption, which is derived from the ozone concentration and particle size effects on reaction kinetics, plays an important role during the reaction. Comparison of the kapp values corresponding to OA, LA and LOA shows the positive correlation between double bonds and reaction rate. In the view of RH effect, both kapp and γ are strongly enhanced by over a factor of three for the LOA/O3 reaction system as the relative humidity (RH) increases from ∼0% to 83%. The LA/O3 reaction system exhibits a weaker RH dependence. In contrast, the kapp and γ of the OA/O3 reaction system are independent of the RH changes. Moreover, the various hygroscopicities of the three acids and corresponding products lead to different reactivities.

Graphical abstract: Kinetics study of heterogeneous reactions of ozone with unsaturated fatty acid single droplets using micro-FTIR spectroscopy

Supplementary files

Article information

Article type
Paper
Submitted
14 Oct 2016
Accepted
27 Nov 2016
First published
13 Jan 2017
This article is Open Access
Creative Commons BY license

RSC Adv., 2017,7, 3204-3213

Kinetics study of heterogeneous reactions of ozone with unsaturated fatty acid single droplets using micro-FTIR spectroscopy

X. He, C. Leng, S. Pang and Y. Zhang, RSC Adv., 2017, 7, 3204 DOI: 10.1039/C6RA25255A

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