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Atmospheric Chemistry of Titan
Juramike
post May 2 2010, 03:38 AM
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Here is a "Benzene-O-Vision" graphic showing the amount of benzene and phenyl radicals at high altitudes on Titan. This is based on detections of benzene and phenyl radical (which recombined in the sample chamber to make benzene) using the INMS instrument during closest approach. The numbers are normalized to constant pressure altitude, roughly 1000 km.

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The data was taken from Table 1 in: Vuitton et al, Journal of Geophysical Research 113 (2008) E05007. "Formation and distribution of benzene on Titan". doi: 10.1029/2007JE002997 [EDIT 5/24/10: Article freely available here] and overlaid on a map of Titan.

The authors mentioned that the errors in these measurements are 20%.

These detections are well above the detached haze layer. Most are at the same sun azimuth angle. (T23 observation had the lowest angle.) Assuming that the temporal difference is minimal (each dot is from a different flyby), there doesn't appear to be an obvious correlation with latitude.

This graphic does show that benzene is present even waaaay up in the thermosphere and ionosphere.


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Juramike
post May 31 2010, 04:57 AM
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It turns out that the methane is only part of the story. The other non-carbon containing gases present also make a huge difference in the types of chemistry and the amount of products. An interesting experiment was done by Imanaka an Smith (Imanaka and Smith, J. Physical Chem. A. 113 (2009) 11187-11194) as summarized in the graphic below:

Attached Image


The authors found that when methane was irradiated in the presence of Argon or nitrogen, they got lots of unsaturated complex organics. In pure methane, the yield dropped, which is counterintuitive, since there is more methane in pure methane. And when methane was diluted with hydrogen, the yield dropped and only simple saturated compounds were produced. The best yeilds in their study was when methane was diluted with N2 or Ar. This is strange, because N2 or Ar are not even incorporated in the products, what gives?

A detailed look at the chemical mechanisms involved reveals the answerÖ


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Posts in this topic
- Juramike   Atmospheric Chemistry of Titan   May 2 2010, 03:38 AM
- - Juramike   Into the Wierdness: Ion-neutral chemistry (A maj...   May 5 2010, 02:59 AM
- - ngunn   Thanks for that very interesting explanation Mike....   May 6 2010, 11:20 AM
- - Juramike   The radical cationic, carbonium, and carbenium spe...   May 6 2010, 01:50 PM
|- - Littlebit   QUOTE (Juramike @ May 6 2010, 06:50 AM) T...   May 11 2010, 09:22 PM
|- - ngunn   QUOTE (Littlebit @ May 11 2010, 10:22 PM)...   May 11 2010, 09:56 PM
- - Juramike   Cute. To be really, really anal, a radical shoul...   May 12 2010, 12:30 AM
- - Juramike   Purple Haze or Where Itís At A paper by Lavvas et...   May 12 2010, 11:46 PM
|- - rlorenz   QUOTE (Juramike @ May 12 2010, 06:46 PM) ...   May 20 2010, 07:17 PM
- - Juramike   Titan's organic chemistry is driven by photoch...   May 16 2010, 09:52 PM
- - Juramike   Titan's Chaotic Chemistry Titan is a syntheti...   May 18 2010, 12:30 AM
- - Juramike   Many ways to fall Below is a graphic showing an e...   May 20 2010, 04:17 AM
- - Juramike   I agree that the reality is probably a lot more co...   May 21 2010, 05:42 PM
- - Juramike   It turns out that the methane is only part of the ...   May 31 2010, 04:57 AM
- - Juramike   In the presence of N2 or Ar, ionization occurs fir...   Jun 1 2010, 03:36 AM
|- - Littlebit   QUOTE (Juramike @ May 31 2010, 08:36 PM) ...   Jun 1 2010, 07:59 PM
- - Juramike   Nitrogen does get incorporated. It is primarily i...   Jun 1 2010, 08:34 PM
- - Juramike   So what does CH5+ do? Basically(!), not much....   Jun 2 2010, 04:15 AM
- - Juramike   Even on electron quenching of the CH5+ radical, it...   Jun 3 2010, 03:32 AM
- - ngunn   About Titan chemistry, not necessarily atmospheric...   Jun 3 2010, 09:01 PM
- - Juramike   Great catch!! From the press release: ...   Jun 4 2010, 12:38 AM
- - Bill Harris   Mike, This has been a good discussion of the chem...   Jun 4 2010, 10:02 PM
- - Juramike   The low temperatures at the surface and lower atmo...   Jun 4 2010, 10:49 PM
- - Juramike   For the moment, the Clark et al. paper can be foun...   Jun 4 2010, 10:52 PM
- - Juramike   Article in press: Strobel, D.F. Icarus (2010) Art...   Jun 6 2010, 07:58 PM
- - Juramike   H2 is the key reagent that shunts the pathway to t...   Jun 8 2010, 12:43 AM
- - Juramike   Titanís atmospheric chemistry is driven by sunligh...   Jun 9 2010, 02:16 AM
- - remcook   Starting on Monday: http://fd147.univ-rennes1.fr/a...   Jun 9 2010, 07:04 AM
- - Juramike   Very cool! Here is an EXCEL conditional forma...   Jun 10 2010, 02:58 AM
|- - rlorenz   QUOTE (Juramike @ Jun 9 2010, 09:58 PM) H...   Jun 12 2010, 01:00 AM
|- - Juramike   As requested (twice now) here is a comparison of s...   Aug 25 2010, 01:41 AM
- - Bill Harris   This is mindboggling. The potential scope of the...   Jun 10 2010, 02:31 PM
- - Shaka   Will the final exam be essay or multiple choice?   Jun 10 2010, 11:59 PM
- - Juramike   I'm gonna give away the answers!   Jun 11 2010, 12:30 AM
- - Juramike   Enter the mechanism Over the next several graphic...   Jun 11 2010, 05:51 AM
- - Bill Harris   QUOTE (Juramike @ Jun 10 2010, 07:30 PM) ...   Jun 11 2010, 04:13 PM
- - Juramike   Ethane (C2H6) [CH3CH3] Almost all ethane is for...   Jun 12 2010, 03:40 AM
- - Juramike   Ethylene (C2H4) [H2C=CH2] Ethylene is a key inter...   Jun 13 2010, 03:21 AM
- - Juramike   Acetylene (C2H2) [HCCH] Acetylene has several for...   Jun 14 2010, 02:52 AM
- - Juramike   Methyl acetylene (1-propyne) (C3H4) [CH3CCH] This...   Jun 15 2010, 02:58 AM
- - jekbradbury   QUOTE (Juramike @ Jun 14 2010, 10:58 PM) ...   Jun 15 2010, 07:35 PM
- - Juramike   Whoops. You are right, it is allene not cumene. ...   Jun 15 2010, 10:39 PM
- - Juramike   [Well, whaddya know...cyclopropenone has been dete...   Jun 16 2010, 09:28 PM
- - Juramike   Ethyl radical (.C2H5) [.CH2CH3] - key intermediate...   Jun 17 2010, 01:46 AM
- - Bill Harris   Mike, one thing I notice is that many of the react...   Jun 17 2010, 02:47 AM
- - Juramike   H+?? Dangit. Those should all be H. hydrogen r...   Jun 17 2010, 03:03 AM
- - Bill Harris   Oh, H-radical as in "H-dot"? They look...   Jun 17 2010, 05:08 AM
- - Juramike   Alright y'all, I'm real sorry about this, ...   Jun 19 2010, 03:06 AM
- - Juramike   Propane (C3H8) [CH3CH2CH3] The straightforward ...   Jun 19 2010, 03:21 AM
- - Juramike   Went back and fixed all diagrams in the different ...   Jun 19 2010, 12:45 PM
- - Bill Harris   Looks good, Mike. Sorry to have tossed a monkey w...   Jun 20 2010, 07:18 PM
- - Juramike   Diacetylene (C4H2) [HCC-CCH] - also known as Buta...   Jun 22 2010, 10:59 PM
- - Juramike   1,3-Butadiene (C4H6) [H2C=CHCHCH=CH2] The forma...   Jun 25 2010, 04:39 AM
- - PDP8E   Mike, you had me at H2O pdp8e   Jun 25 2010, 04:52 AM
|- - Juramike   QUOTE (PDP8E @ Jun 25 2010, 12:52 AM) Mik...   Jun 26 2010, 05:00 AM
- - Juramike   1-Butene (C4H8) [H2C=CHCH2CH3] 1-Butene is 1,3-...   Jun 26 2010, 04:57 AM
- - Juramike   n-Butane (C4H10) [CH3CH2CH2CH3] Boring butane c...   Jun 29 2010, 04:03 AM
- - Juramike   Benzene (C6H6) At lower altitudes, benzene is f...   Jun 30 2010, 03:56 AM
- - Juramike   Benzene (C6H6) high altitude ion route At highe...   Jul 1 2010, 12:31 AM
- - Juramike   Structure of Benzenium (C6H7+) This is one of t...   Jul 2 2010, 12:46 AM
- - Juramike   Beyond Benzene - PAH's and Polyphenyls Polyar...   Jul 4 2010, 01:46 AM
- - Bill Harris   The genesis of Titan's atmosphere may be more ...   Jul 8 2010, 12:44 PM
- - Juramike   HCN The incorporation of nitrogen into Titanís ...   Jul 13 2010, 12:00 AM
- - Juramike   .CN radical - key intermediate The formation of...   Jul 14 2010, 12:11 AM
- - Juramike   Cyanomethlyene carbene [:CH(CN)] A very recent...   Jul 19 2010, 12:03 AM
- - GEmin   QUOTE The first experimental evidence showing how ...   Jul 19 2010, 06:36 AM
- - Juramike   Acetonitrile (CH3CN) There are multiple ways to...   Jul 21 2010, 02:08 AM
- - Juramike   Cyanoacetylene (HC3N) [HCC-CN] The dominant mec...   Jul 22 2010, 01:13 AM
- - Juramike   Cyanogen (C2N2) [NC-CN] According to the Krasno...   Jul 23 2010, 12:17 PM
- - Juramike   Dicyanoacetylene (C4N2) [NC-CC-CN] Two differen...   Jul 25 2010, 04:04 PM
- - Juramike   Acrylonitrile (C2H3CN) [H2C=CHCN] This molecule...   Jul 29 2010, 10:42 PM
- - Juramike   Iíve tried to represent Titanís chemistry in a sli...   Aug 2 2010, 03:02 AM
- - Juramike   The graphic below shows the pattern of dominant re...   Aug 22 2010, 08:06 PM
- - Juramike   Estimated depths solids vs. liquids from the vario...   Aug 25 2010, 02:25 AM
- - Juramike   A recent DPS abstract discusses some possibilities...   Oct 8 2010, 02:26 PM
- - titanicrivers   Thanks for the discussion and the link Mike. One ...   Oct 8 2010, 03:46 PM
- - Juramike   Most of the formation chemistry seems to be happen...   Oct 8 2010, 05:21 PM
- - Juramike   LPSC 2011 abstract describes continuing efforts to...   Jan 30 2011, 04:07 AM
- - Juramike   Detection of high altitude cirrus clouds in Titan...   Feb 3 2011, 07:01 PM
- - centsworth_II   This gives hope of much greater understanding of T...   Feb 9 2011, 04:32 PM
- - ngunn   Interesting link posted on the Cassini Huygens Yah...   May 10 2011, 10:56 AM
- - Juramike   The Cool Way to PAH's in Titan's Upper Atm...   Jul 3 2011, 12:55 AM
- - scalbers   I saw a talk given at the AGU conference last week...   Dec 11 2011, 08:39 PM
- - Paolo   not sure this is the best topic to post it to, thi...   Jan 5 2012, 10:51 AM


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