Experimental and theoretical studies of reactions important in photochemical smog : aromatics and alkanes

Author: Andino, Jean Marie

Year: 1996

Degree: Dissertation (Ph.D.)

Advisors: Seinfeld, John H.; Flagan, Richard C.

Committee Member: Unknown, Unknown

Option: Chemical Engineering

DOI: 10.7907/4811-nz89

Abstract

The development of effective ozone control strategies requires the use of atmospheric models. There is general agreement within the scientific community that several aspects of the chemistry within these models has yet to be fully elucidated, and is influential in their predictions. The work in this thesis is aimed at trying to determine some of the unknown aspects of the mechanisms of important atmospheric species. Specifically, the gas-phase reactions of two large alkanes, 2,2,4-trimethylpentane and 2,2,5-trimethylhexane are investigated. These two alkanes are present in urban air, and are potential aerosol precursors. The chemistry of several aromatic hydrocarbons are also studied using both theoretical and experimental techniques. The effects of NO2 on the photooxidation of toluene, m-xylene, and p-xylene are examined, and mechanisms of each of these organics are thouroughly evaluated through closely coordinated laboratory work and computer modeling. In addition, product studies of the photooxidation of 1,2,4-trimethylbenzene and m-ethyltoluene are conducted. These studies provide the first identification of ring-retained products from 1,2,4-trimethylbenzene, and ring-retained and fragmented products from m-ethyltoluene.

A new indoor experimental reactor was designed to investigate gas-phase reaction kinetics and mechanisms. This new system has served to launch the atmospheric chemistry program at Caltech into a wide variety of new research topics.

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