Issue 38, 2006

The uptake of O3 by myristic acid–oleic acid mixed particles: evidence for solid surface layers

Abstract

The oleic acid ozonolysis in mixed oleic and myristic acid particles was studied in a flow tube reactor using single particle mass spectrometry. The change in reactivity was investigated as a function of the myristic acid concentration in these 2 micron particles. For pure oleic acid aerosol, the reactive ozone uptake coefficient, γ, was found to be 3.4 (±0.3) × 10−4 after taking secondary reactions into account. At the myristic acid crystallization point, where only 2.5% of the particle is in the solid phase, the uptake coefficient was reduced to 9.7 (±1.0) × 10−5. This dramatic drop in the uptake coefficient is explained by the presence of a crystalline monolayer of myristic acid, through which ozone diffusion is reduced by several orders of magnitude, relative to liquid oleic acid. Scanning electron microscope images of the mixed particles confirm that the particle surface is crystalline when the myristic acid mole fraction exceeds 0.125. The findings of these experiments illustrate that particle morphology is important to understanding the reactivity of species in a mixed particle. The decay of myristic acid during the course of ozonolysis is explained in terms of a reaction with stabilized Criegee intermediates, which attack the acidic groups of the oleic and myristic acids with equal rate constants.

Graphical abstract: The uptake of O3 by myristic acid–oleic acid mixed particles: evidence for solid surface layers

Article information

Article type
Paper
Submitted
11 Jul 2006
Accepted
16 Aug 2006
First published
24 Aug 2006

Phys. Chem. Chem. Phys., 2006,8, 4468-4475

The uptake of O3 by myristic acidoleic acid mixed particles: evidence for solid surface layers

D. G. Nash, M. P. Tolocka and T. Baer, Phys. Chem. Chem. Phys., 2006, 8, 4468 DOI: 10.1039/B609855J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements