Atmospheric Chemistry of Titan |
Atmospheric Chemistry of Titan |
May 2 2010, 03:38 AM
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
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.
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. -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Jul 14 2010, 12:11 AM
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
.CN radical - key intermediate
The formation of .CN: radical is very straightforward: Higher energy photon hits HCN, causes dissociation of H-C bond, and you get H. and .CN: radical. .CN: indicates that the radical electron resides on the carbon atom, that the triple bond between carbon and nitrogen still exists, and that the lone pair is still on nitrogen (in an sp-orbital sticking straight out along the axis of the C-N triple bond.). Likewise the radical electron resides in the sp-orbital on the carbon and sticks straight out as well along the axis of the C-N bond away from the triple bond electrons. This molecule is linear, like acetylene. .CN: radical can play a key role in the formation of cyanoacetylene [HCCCN], cyanogen [NC-CN], and dicyanoacetylene [NC-CC-CN], although there are alternative mechanisms for these compounds that proceed through cyanomethylene carbene (:CH(CN)). -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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