Linoleic Acid -> ... -> Hexanal

I need some help here, so I put this in beginnings instead of organics. I'm not too seasoned with organic chem(seasoned get it har har food chem...). The goal here is to synthesize/obtain hexanal from oxidation of linoleic acid.

Here is what I do know . Triglycerides -> hydroperoxides -> short chain aldehydes via oxidation. {http://www.separationsnow.com/coi/cda/detail.cda?chId=1&id=16241&type=Feature&page=1}

Linoleic acid comprises of ~68% of sunflower oil, or for a more common cooking oil ~21% of canola oil.{http://en.wikipedia.org/wiki/Linoleic_acid} Simple enough to obtain, possibly hydrolyze, vac distill, or purchase without issue.


(the last link provided in this threads supplies theoretical rxn schemes and lots of information I can't quite all piece together).

Now to the real 'meat' of the issue. I'm trying to understand the entire scope of what is going on here. So as to hopefully obtain a usable quantity of hexanal. So it goes(correct me if I am understanding this wrong)

1. Linoleic Acid -> 9-hydroperoxides + 13-hydroperoxides via autoxidation
2. 13-hydroperoxide -> hexanal via retroaldolization
3. 9-hydroperoxide -> 2,4-decadienal via retroaldolization
4. 2,4-decadienal -> 2-octenal, hexanal via retroaldolization
{Page 75: Meat science and applications By Y. H. Hui, Yiu H. Hui.
http://books.google.com/books?id=651Zv5hUzyIC&pg=PA75&lpg=PA75&dq=triglyceride+oxidation+hexanal&source=bl&ots=uQQR3uM0dw&sig= wPj7soKAqym2VjE2i_kR6iy91fw&hl=en&ei=__woTaabCcXflgfYobXpAQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBMQ6AEwAA#v=onepa ge&q=triglyceride%20oxidation%20hexanal&f=false}

so to elaborate further on the actual experimental(here's where I need help).

1. Linoleic acid autoxidation, could occur simply by letting it sit for a few weeks near a window somewhat warm. I would be tempted to put some H2O2 in to provide the free-radicals but I'm not sure if this would change the oxidation products. Photoxidation is an option but it seems impractical judging on how food spoils on its own.

2. Wouldn't we want to be protonating the hydroperoxide here with a dehydrating acid such as sulphuric?

3,4. Wouldn't the the retroaldolization be catalyzed by water?

Then steam distill the final product to obtain hexanal.

{Food Chemistry By H. -D. Belitz, Werner Grosch, Peter Schieberle : http://books.google.com/books?id=xteiARU46SQC&pg=PA205&lpg=PA205&dq=linoleic+acid+to+hexanal&source=bl&ots=HyNrdMSRrC&sig=wKAI Go0nrYLco9iu7Pm0jVpm_Zg&hl=en&ei=-gQpTeTaF8aAlAe_uOTXAQ&sa=X&oi=book_result&ct=result&resnum=9&ved=0CFIQ6AEwCA#v=onepage&a mp;q=linoleic%20acid%20to%20hexanal&f=false}

Thanks to any help sorry this is a mess of a thread and I can hardly carry my own weight here. Been struggling to find grounded information on the net. The primary focus it seems is how the compound is possibly made when oil spoils, not so much how to make the compound from spoiling oil. Being a novice this makes it much harder to figure out what exactly going on.

I am aware that there is a orgsyn procedure on this but it goes beyond my means/home-lab and this seems like much easier/cheaper way to go about it, if a decent method could be understood. I want to experiment on it, but I fancy knowing whether or not I'm on the right track or not first.

They can do this with enzymes it seems with good success. Looking for a more ochem approach.
http://www.springerlink.com/content/v3410430913t5820/

If you saw this post on another forum I apologize but I don't think anyone is really going to take the time to help me out over there...

Thanks again.

[Edited on 9-1-2011 by smaerd]

I attached the full text of the paper you posted.

Some further infomation can be found here (ricinoleic acid--> heptanal + undecylenic acid).

http://www.sciencemadness.org/talk/viewthread.php?tid=11645#...

I thought this one was really cool, but I got side-tracked and never got around to looking into it. Maybe I'll get to it this time, . And, this time, it looks like the enzymic route must be examined as well (72% yield from that mess is OK).

Now then, where to get those enzymes? Ah, here is another route that might get us there using a (crude) enzyme isolate from soybeans (can't upload it, too big, but it's: Gardner et al. 1991. plant physiol, 97, pp. 1059-1072).

Cheers,
O3

Hmm... The file will not upload? Ah. Crap, it exceeds 2 Mb.


[Edited on 9-1-2011 by Ozone]

Attachment: Marczy et al 2002 Biotechnol. Lett. 24 (20), pp. 1673-1675.pdf (55kB)
This file has been downloaded 503 times

Ah yes I just checked the article(Gardner et al. 1991. plant physiol, 97, pp. 1059-1072) you mention about the crude soybeen isolates. Would love to entertain this idea if I had a centrifuge and a homogenizer amongst other things.

Interesting never even considered pyrolysis. Haven't done one of those reactions before. Pine rosin as a catalyst? Interesting . I'll have to do some research but that seems to possibly be the 'quick and dirty' way to go about it. I bet the clean up stinks, but hey nothing good came easy.

http://www.somaluna.com/prod/pine_rosin.asp(haven't ordered from them cannot vouch)

Good thing there's naturalists out there hehe, if this is actual pine rosin this could be a very affordable experiment.

This is all reminding me how desperately I need to get a fume hood built. Better finish designing that today.

[Edited on 9-1-2011 by smaerd]

Ah yea primary/secondary alcohols only for the swern woops.

Very interesting idea about the Lemeiux-Johnson oxidation I would have never came up with that one(well maybe in a few years )! Sodium periodate preparation looks simple enough so long as I can get my hands on some HNO3 for recrystalization. I might have to try that out first actually.