andyloris
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Replacement for acetonitrile in oxone oxidation
Hi, I'm trying to cleave the double bond in ricinoleic acid to get azelaic acid based on this paper.
They use acetonitrile, but I don't have any.
Can I use an other solvent for this reaction ?
Thanks in advance
Always trust your first idea, especially if you only have one.
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clearly_not_atara
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Possibly, but very possibly not. Acetonitrile "catalyzes" certain oxidations with oxone by forming the iminoperacid intermediate and its cation
C(=NH2+)OOH, being hydrated in the process to acetamide.
Acetonitrile however can be produced by refluxing acetamide over alumina (240 C) or by heating acetamide with a V2O3/hydrotalcite (by depositing VCl3
on hydrotalcite) catalyst at 170 C.
Also, thanks for dredging up that paper. I remembered that there was an oxone/acetonitrile alkene cleavage method reported once, but then I couldn't
find it again. Good to know that my memory isn't making things up.
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Fery
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This is not exactly answer to your question but I already did 2 different syntesis of azelaic acid:
oleic acid + H2O2 + cat. H2WO4
ricinoleic acid + KMnO4
Both are suitable for lab. preparation. In industry they use O3
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andyloris
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Thank you very much !
Would the pertungstic acid oxidation work with ricinoleic acid ?
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Fery
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Yes of course. The catalyst was pertungstic acid. I dissolved part of 99,6% W TIG welding electrode in 30% H2O2. Dissolution lasted about 1 week
(maybe could warry according inhibitor type and amount used for stabilizing H2O2 ???). The dissolution must be watched not to allow yellow solid to
start to separate (small amount do not hurt but then more complicated to calculate concentration of dissolved W). You can measure the weight decrease
of the electrode and then use only part of the solution. If you let the electrode in H2O2 for too long, H2O2 is consumed and some solid starts to
separate, very likely WO3 (I only guess there could be a reaction to produce H2O2 to continue W dissolution by reaction H2WO5 -> WO3 (s) + H2O2)
and WO3 was insoluble even after adding fresh H2O2 (I do not know why, maybe long stirring could dissolve it??? just an idea, I did not try). I did
not succeed in dissolving either commercial WO3 in H2O2. Dissolution was at room temperature. The temperature of unsaturated fatty acid oxidation
should be 100 C, but not more. If it reached 103-105 C it started to accelerate exothermic decomposition of H2O2 (decreasing yield and risk of
runaway). It was very difficult to keep the temp at 100 C, I had to be present for the whole time and used a cloth wetted with cold water to cool the
wall of reactor flask to lower T back to 100 C. Also good stirring is necessary as the reaction is 2-phase, the phases not soluble in each other.
Maybe instead of H2O2 it could run with Na2S2O8 ??? I did not try Na2S2O8, just an idea...
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andyloris
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Can 12% hydrogen peroxide be used for dissolving the tungsten ? (I don't have 30% hydrogen peroxide)
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Boffis
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Does anyone have any idea if this method would work on conjugate dienes like sorbic acid and piperine? What would the product be? Would sorbic acid
give one mole of acetic acid and 2 of oxalic acid?
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Fery
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Boffis - maybe due to conjugation couldn't sorbic acid split into propionic acid + malonic acid ??? Just my wild idea...
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unionised
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Quote: Originally posted by Boffis  | | Does anyone have any idea if this method would work on conjugate dienes like sorbic acid and piperine? What would the product be? Would sorbic acid
give one mole of acetic acid and 2 of oxalic acid? |
Permanganate oxidises oxalic acid quite quickly.
I think the alkaline conditions would hydrolyse piperidine.
The piperine might survive but the rest of the molecule would get chewed up badly.
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Keras
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| Quote: Originally posted by clearly_not_atara |
Also, thanks for dredging up that paper. I remembered that there was an oxone/acetonitrile alkene cleavage method reported once, but then I couldn't
find it again. Good to know that my memory isn't making things up. |
I second that. I wasn't aware Oxone could do that, I thought it was privilege of potassium permanganate alone (if we discount ozone). Nice to know
Oxone works, since I have tons of it (and also acetonitrile). I’ll test that when it comes handy for me.
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SyntheticFunk
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Not only can Oxone and KMnO4 do it, but there is a NaIO4/RuCl3 system that is also capable of cleaving alkenes to carbonyls with the solvent system
having a dramatic effect on the specific oxidation. It can be adjusted to select for ketones, aldehydes, or carboxylic acids. While several procedures
call for acetonitrile with NaIO4/RuCl3, there are some that do not which may be of use to you. Here is a reference I got from a quick google.
Attachment: Murahashi, S.-I., & Komiya, N. (2010). RutheniumCatalyzed Oxidation for Organic SynthesisModern Oxidation Methods.pdf (299kB)
This file has been downloaded 669 times
[Edited on 22-1-2023 by SyntheticFunk]
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Keras
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Isn’t NaIO₄ explosive?
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Mateo_swe
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Just buy acetonitrile, you are in Europe.
If you cant get it ask one of the sellers in the "Reagents and Apparatus Acquisition" section.
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SyntheticFunk
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Keras to my knowledge it is not a major explosion hazard, at least no more explosive than most other oxidizing agents. I've worked with it a few times
and havent had any issues. An SDS I read did mention the risk of fire or explosion, but also referred to it as stable. In my case the sodium periodate
system had the benefit of cleaving the alkene completely within 2 hours at room temp vs 24 for permanganate. It didn't even require an inert
atmosphere or any special precautions
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Keras
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Okay, I might have been mixing it up with something else.
| Quote: Originally posted by SyntheticFunk | | cleaving the alkene completely within 2 hours at room temp vs 24 for permanganate. It didn't even require an inert atmosphere or any special
precautions |
Doesn’t alkene cleavage with periodate require prior diol-formation with osmium tetroxide?
[Edited on 23-1-2023 by Keras]
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SyntheticFunk
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Not necessarily! There are some protocols that form the diol with permanganate first or osmium tetroxide, but ruthenium can also facilitate the
transformation of alkenes to diols. It's a very nice procedure over all and avoids a lot of the issues associated with the other methods like using
OsO4
Take a look here:
https://www.organic-chemistry.org/chemicals/oxidations/ruthe...
[Edited on 23-1-2023 by SyntheticFunk]
[Edited on 23-1-2023 by SyntheticFunk]
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clearly_not_atara
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I've been aware of the ruthenium methodology for some time, but I'm confused as to what situation could make acetonitrile inaccessible and
ruthenium available?
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andyloris
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Osmium tetroxide is too scary (I don't want do be blind), and ruthenium is expensive.
I read that acetonitrile was a contact poison, which is one of the reasons I wanted to avoid it.
After some more searching, I found another paper in which they use K10-montmorillonite supported ceric ammonium nitrate for this reaction.
Has anyone tried this method ?
Always trust your first idea, especially if you only have one.
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SyntheticFunk
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| Quote: Originally posted by clearly_not_atara | | I've been aware of the ruthenium methodology for some time, but I'm confused as to what situation could make acetonitrile inaccessible and
ruthenium available? |
A fair criticism assuming you are referring to accessibility. It does have the benefit of being catalytic so one need only acquire it once, though
admittedly recovering it has been too difficult to be worthwhile in my experience. If you are referring to the solvent conditions I believe there are
procedures that omit acetonitrile.
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woelen
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NaIO4 is not explosive, but it is capable of making fires more severe. In a solvent system with a low percentage of NaIO4 in the total mix, I would
not worry about that. Only solid mixes of NaIO4 with strong reductors/fuels, like metal powders, powdered sulfur, or powdered organics can burn
violently, when ignited.
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Keras
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Must've mixed it up with some other iodine (VII) compound. The Dess-Martin periodinane, probably. Which, by the way, is an iodine (V) compound, not
(VII) as I believed.
[Edited on 24-1-2023 by Keras]
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