Title:

ICARUS Chamber Experiment: 2014 FIXCIT Study_20140124_4-hydroxy-3-nitrooxy ISOPN/Methyl nitrite/nitric oxide/_Hydroxyl radical_Ammonium sulfate_4,3-isoprene hydroxynitrate + OH, high NO, 50% RH, (NH4)2SO4 seed


Description:

Goals:
To observe the products of 4-OH-3-ONO2-ISOPN + OH oxidation in the presence of wet ammonium sulfate seeds.  In particular, we would like to achieve a constraint on the yield of the dihydroxydinitrate (DHDN) product.  In addition to DHDN, expected products include C4-hydroxy-carbonyl nitrate (MVKN, mm=149), formaldehyde, hydroxyacetone, and glycolaldehyde.

We also explored GTHOS OH interference at the end of the experiment. We conclusively saw increasing interference once NO was titrated out of the bag, and significant amounts of ozone were present. It scaled with ozone addition.

Summary:
John Crounse successfully separated most of the hexanes/ethyl acetate from a synthesized sample of 4,3 ISOPN. RH was added to the bag to 55%. GHTOS managed to grab a humid background, which is key. Isoprene hydroxy nitrate was successfully added to the bag. No impurities were noticed on the GC from the 4,3 ISOPN std. Lights were turned on (we should do it off-hour so that NO-CL can measure right when lights turn on/off). Mostly the methylvinylketone nitrate (MVKN, MW = 149) was made. AMS noticed about 4ug/m3 of organic mass, and TD-LIF reported ~70ppt of aerosol particles. After about 2 hours, oxidation significantly slowed down. When 100% lights on, oxidation sped up a bit, but leveled off, as did NO concentration, indicating a lack of OH. Potentially significant photolysis of m234 was noticed.

When lights were turned off, everything stabilized. There was enough NO to completely titrate the roughly 20ppb O3 that had formed during the experiment. After lights off, multiple levels of O3 were added to the bag to explore wthe OH interference question.

Organization: 2014 FIXCIT Study
Lab Affiliation: California Institute of Technology
Chamber: Seinfeld chambers

Experiment Category: Gas phase chemical reaction, Aerosol formation
Oxidant: Hydroxyl radical
Reactants: 4-hydroxy-3-nitrooxy ISOPN, Methyl nitrite, nitric oxide
Reaction Type: Photooxidation
Relative Humidity: 52
Temperature: 26
Seed Name: Ammonium sulfate
Pressure: 750 Torr


Metadata URL:

https://gdex.ucar.edu/dataset/id/48963b8e-111f-41e7-adff-3dc5593c3c4d.html