Explorations of infrared spectra of criegee intermediates and their reactions

Lee, Yuan-Pern

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https://hdl.handle.net/2142/100686 Copy

Description

Title

Explorations of infrared spectra of criegee intermediates and their reactions

Author(s)

Lee, Yuan-Pern

Issue Date

2018-06-18

Keyword(s)

Plenary

Abstract

Criegee intermediates, carbonyl oxides produced in ozonolysis of unsaturated hydrocarbons, play important roles in atmospheric chemistry. A new production scheme using photolysis of R2CI2 + O2 facilitated the production and direct detection of Criegee intermediates with various spectral techniques and has stimulated rapidly expanding research.a,b Our understanding of important atmospheric reactions involving Criegee intermediates is becoming clarified because of the direct probing of Criegee intermediates in kinetic experiments. The infrared spectra of CH2OO,c,d CH3CHOO,e and (CH3)2COOf have been recorded with a step-scan FTIR with resolution 0.25 to 1 cm−1 ; rotational contours with unresolved rotational lines were reported. On employing a quantum cascade laser coupled with a Herriot cell, we recorded spectra of the O-O stretching bands of CH2OO and CH3CHOO in the region 880-932 cm−1 at resolution 0.002 cm−1 . In addition to improved rotational parameters, perturbation was observed at high-J levels of Ka = 3, 6, and 11 of CH2OO. Distinct lines of syn- and anti-CH3CHOO were also observed. Kinetic investigations based on this new experimental scheme will be presented. Taking advantage of the wide spectral coverage of an FTIR, we investigated the mechanism of the reactions of CH2OO with SO2, HNO3, HCl, and HCOOH. For example, in the reaction of CH2OO + HCOOH, eight observed bands are assigned to hydroperoxymethyl formate HPMF (P5). In the later reaction period, three bands are assigned to an isomer HPMF (P6) and three bands to the final product, anti-FAN. According to our kinetic analysis, only P5, not P6, decomposes to form FAN.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/100686

DOI

10.15278/isms.2018.MA04

Copyright and License Information

Copyright 2018 Yuan-Pern Lee

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