[MOS] 3/10: Lord Lecture with Marsha Lester (University of Pennsylvania)

[Christine Brooks]

Please join us for the 2020 Lord Lecture
presented by
Professor Marsha I. Lester
University of Pennsylvania

Tuesday, March 10, 2020
in the Grier Room (34-401A)<https://whereis.mit.edu/?go=34> at MIT


“Spectroscopic and Dynamical Probes of Alkene Ozonolysis Reaction Pathways”

Alkene ozonolysis is a primary oxidation pathway for alkenes, the most abundant organic compounds in the Earth’s troposphere after methane, and also an important source of atmospheric hydroxyl (OH) radicals. Alkene ozonolysis takes place through a complicated reaction pathway with multiple intermediates and barriers on the way to OH radicals and other products. A carbonyl oxide species, known as the Criegee intermediate (RR•COO), represents a critical branching point on the pathway that controls the products formed in this important class of reactions. Recent studies in this laboratory are focused on four-carbon Criegee intermediates, including unsaturated methyl vinyl ketone oxide (MVK-oxide) and methacrolein oxide (MACR-oxide) derived from isoprene ozonolysis. The Criegee intermediates are generated by alternative synthetic routes, characterized utilizing infrared and ultraviolet spectroscopic methods, and probed to examine the resultant dynamics. Infrared ‘fingerprint’ and electronic spectra reflecting •-conjugation of the Criegee intermediates are obtained, along with time- and energy-resolved studies of their unimolecular decay to OH radical products. The conformation and nature of the substituents (R, R•) of the Criegee intermediates are found to have a profound effect on their reaction dynamics. Complementary experiments under thermal conditions reveal the first direct kinetic measurements of MVK-oxide reactions with key tropospheric species and, along with theoretical modeling, provide insights on the impact of Criegee intermediates in the atmosphere.

Refreshments will be served following the lecture
No RSVP is required to attend

Christine Brooks
Administrative Assistant
Massachusetts Institute of Technology
Department of Chemistry
77 Massachusetts Ave, 6-333
Cambridge, MA 02139
p: 617.253.7239
e: cbrooks at mit.edu<mailto:cbrooks at mit.edu>

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