Experiment: Caltech Atmospheric Chamber_20140816_2-Methyl-3-buten-1-ol/Methyl nitrite/10102-44-0/OZONE_Hydroxyl radical_No Seed_Dry


Name: Caltech Atmospheric Chamber_20140816_2-Methyl-3-buten-1-ol/Methyl nitrite/10102-44-0/OZONE_Hydroxyl radical_No Seed_Dry
Date: 2014-08-16

Caltech Atmospheric Chamber

Near/Far Bag 2012-2015 (Tran)

Experiment Set
MPAN, Methacrolein, Isobutyraldehyde, and 231MBO photoxidation experiments

This experiment was done to react 2-Methyl-3-buten-1-ol (231 MBO) with ozone to produce the Hydroxymethylpropanal (HMPR). After oxidizing HMPR with OH in the high NO2 condition, we get the HMPR-PAN (or the peroxynitrate of HMPR). This is analogous to MPAN except it has an OH at the 1-position and no double bond, so that when OH abstracts a hydrogen from HMPR-PAN, it makes the exact same alkyl radical as OH addition to MPAN. The only difference is that the alkyl radical from OH + HMPR-PAN is not created with excess energy, compared to OH addition radicals. Thus...the thermalized radical from HMPR-PAN is not hypothesized to have enough energy to form HMML, and therefore wont form secondary organic aerosol (SOA).

The reaction did not produce any significant amounts of SOA from the OH+HMPR-PAN reaction. Therefore the hypothesis is validated, that the alkyl radical of MPAN +OH goes to HMML because it is formed with excess energy through OH addition. We showed the exact same alkyl radical with less energy will add O2 instead of decomposing to HMML.

Additional Notes
This experiment is #11 in the PCCP paper, and shown in Figure S6. The mechanism is shown in Figure 6.

Experiment Details


  • Gas phase chemical reaction
  • Aerosol formation
Temperature: 25
Relative Humidity: 4
Seeded Experiment: No
Fuchs Adjusted Surface Area:
Condensation sink rate coefficient: 4
Reaction type:
Oxidant Name: Hydroxyl radical
Initial Oxidant Concentration Value: 2e7 (molecules_per_cubic_centimeter)
RO2 Main Fate: NO2
RO2 Lifetime: (Seconds)
Pressure: 750 Torr

Data Set plots
Choose a file: Choose the X-Axis:

Experiment Set Details

Name: MPAN, Methacrolein, Isobutyraldehyde, and 231MBO photoxidation experiments
Time format and units: Experiment time (minutes, local)
Photoxidation of synthesized methacryloyl peroxynitrate (MPAN) to understand its pathways of SOA formation, leading to 2-methylglyceric acid in the particle phase. It is hypothesized that MPAN produces an unstable intermediate called HMML (hydroxymethyl methyl-a-lactone) that ring opens when it hits a surface, with co-product NO3. Some experiments were done with alpha-pinene as an NO3 scavenger, with the production of pinene nitroxy hydroperoxide (PNP, m/z 316 C10H17NO5) evidence of the alpha-pinene + NO3 chemistry. Photoxidation of methacrolein (MACR) was performed for comparison. Photooxidation of 2-methyl-but-3-ene-1-ol (231MBO) and isobutyraldehyde were performed because they are (or can produce) analogous compounds that will give insight into the oxidation mechanism. Experiments were mainly performed dry and with no seeds, although 2 experiments were performed on with varying particle liquid water on ammonium sulfate (AS) seeds. Note that particle wall loss has already been applied to SMPS data, but the raw data are also provided as well as the wall loss kinetic parameters.


  • Tran Nguyen UC Davis
  • Paul Wennberg Caltech


Principal investigator:

John H Seinfeld
Phone: (626) 395-4635
E-mail: seinfeld@caltech.edu
OrcID: https://orcid.org/0000-0003-1344-4068

Data Manager:

Stephanie Kong
Phone: 626-395-3194
E-mail: wkong@caltech.edu


Reactant Compound type Concentration Concentration units
2-Methyl-3-buten-1-ol (94292)
  • Alcohol
  • Alkene
200 Parts Per Billion
Methyl nitrite (12231) 200 Parts Per Billion
10102-44-0 (3032552)
  • NOx
100 Parts Per Billion
OZONE (24823) 660 Parts Per Billion

140816_Timeline.csv Timeline

Local time (hh:mm) Action (Time zero is "Ozonolysis start" time - when the MBO gets injected)
10:46 Instruments on (Far bag is at 25 degC)
11:15 Injecting ozone (approx 660 ppb)
13:05 Stopped injecting ozone and mix
13:32 Inject 20 uL of 2-methyl-but-3-ene-1-ol (231MBO) with gentle heating and lots of mixing
13:45 Injections stop (Reaction Start)
15:32 Stopped CIMS to save on reagent gas
17:10 Restart CIMS
21:08 Stopped CIMS again to save on reagent (about 1/3 of MBO left and 450 ppb ozone left - letting this go overnight)
8:50 (next day) Restart CIMS
10:07 Injected 100 ppb of NO2
10:35 Injected 11.4 Torr of CH3ONO (around 200 ppb) as an OH precursor
10:43 Injections stop
10:45 Lights on (10%)
13:43 Lights off

Light Flux Characterizations:
2013-12-13 (#30)
Particle Loss Characterizations:
2013-03-06 (#29)
Vapor Loss Characterizations:

Chamber Details

Name: Near/Far Bag 2012-2015 (Tran)
Volume in cubic meters: 27
Shape: Rectangular Prism
Surface area in cubic meters: 41.8
Flow Mode: Batch
Flow through rate in liters per minute:
Body Material: Teflon
Body thickness: 50
Replacement date:
Replacement frequency: As needed
Cleaning method: Flushing with air
o3 background: 0.5 ppb
nox background: 0.1 ppb for Near, > 0.1 ppb for Far
Particle background in micrograms per cubic meter: < 0.1 ug/m3
Air filtration method: Custom Filter
Mixing method: 0
Mixing method material:
Temparature Control: Yes
Temparature measurements recorded: Yes
Temparature range (min degrees celcius): 20
Temparature range (max degrees celcius): 45
Humidity Control: Yes
Humidity Measurements Recorded: Yes
Relative humidity range (min percent): 5
Relative humidity range (max percent): 100
Particle experiment capability: 1
Lights: Yes
Light source type(s): UVA Black Lamps
Supplemental information: https://www.worldscientific.com/doi/abs/10.1142/9789813147355_0001
Additional Notes: