underground
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piperonal through ozonolysis
This is not my post, it is from another forum. Anyway here it is:
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After weeks of research and several experiments, I have verified a viable procedure to obtain piperonal through ozonolysis A high level of the
procedure can be found below: Piperine hydrolysis to potassium piperinate and distill out piperidine (ChemPlayer style) 2. Potassium piperinate
directly add only H20 and NO HCL you want the potassium salt 3. H2O as the only solvent used reduces risk of dangerous peroxides forming 4. Potassium
piperinate is very soluble in water use a minimal amount to dissolve it (I used 200ml often in my experiments but it will vary on how much potassium
piperinate you are using) 5. Attach bent glass tube to thermometer inlet adapter 6. Place dissolved potassium piperinate/H20 in three neck round
bottom flask and attache ozone generator to bent glass tube 7. A second ozone generator can be used if desired in another one of the flasks neck
joints 8. Do reaction in ice water bath 9. Attach empty thermometer adapter to top neck to slowly allow ozone to leave flask 10. With vigorous
stirring in flask allow ozone generator to bubble O3 into reaction mixture (it will get frothy at the beginning of the reaction) 11. As the reaction
runs the mixture will go from a very dark opaque color to a carmely color and piperonal will visibly precipitate out as the reaction runs. Piperonal
is very insoluble in H2O 12. After the reaction is done, or if you get bored for the day, you can place the reaction mixture in the fridge and lots of
piperonal will precipitate out 13. Following the collection of the precipitate, the reaction mixture can be stored in the fridge. The mixture can then
be returned to the ozonolysis set up another day to continue to precipitate out the remaining piperonal (piperonal on demand) 14. I would recommend
that you still do a extraction with DCM when your done with the fridge precipitations to get that last bit out 15. My current theory is you can use PH
to track the reaction progress (still doing some testing on this). Of course alternatively one could just track progress with TLC 16. HCL can be added
to the solution to see if any remaining piperinic acid precipitate out of solution following completion of ozonolysis 17. An added bonus of this setup
is the piperonal does not get over oxidized nearly as badly as other methods because once it precipitates out of solution the ozone no longer appears
to affects it the same One possible improvement to this procedure is the use of an oxygen concentrator to boost the production of ozone by the
generator. I plan to test this theory and will update the thread if it improves yield and reduces reaction time. |
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After further testing I was able to come up with a way more efficient procedure for the production of piperonal through ozonolysis. This time with the
starting material being piperine instead. Here is how it goes: 1) Starting by weighing out piperine in this case I used 8 g. 2) Dissolve piperine in
ethanol/water mixture with 20% being H2O for this experiment I used 150ml total so 30ml H2O and 120ml C2H6O (200 proof) (I had to heat up the mixture
to get the piperine to dissolve). 3) Using a fritted gas washing bottle packed with glass springs, I poured the ethanol/water/piperine mixture into
the gas washing bottle. 4) To the gas washing bottle I then attached an adjustable airflow outlet containing 6 taps of which I attached an ozone
generator to two of the taps. both ozone generators claimed to generate 1g/hr. 5) I then ran the ozone generators for 8 hrs. 6) At the 6 hour mark I
began taking TLC plates of the reaction and compared them to a reference mixture of ethanol and piperine. The lower spot is piperine and the upper
spot is piperonal. 7) After 8 hours TLC showed that all piperine had been converted to piperonal. 8 ) The reaction mixture was then vacuum distilled
until all the ethanol had been removed. (It must be vacuum distilled I attempted to do a normal distillation and the final product came out as an oil
and not crystals). 9) The remaining reaction mixture was poured into a flask and placed in the fridge after adding 200 additional ml of H20. 10) After
a few hours the piperonal has crystalized out of the reaction mixture and is recovered through vacuum filtration final yield after drying was 4.1 g or
around 95% yield. |
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**Quick Update:** The Arduino-controlled ozone generators have revolutionized the process. I can now continuously generate piperonal throughout the
day with minimal effort. The only requirement is reloading the reaction vessel and refrigerating the finished reaction mixture with added H2O (add
until a cloud appears and persists). A slight variation to the original process has been implemented. The fridge precipitant is now filtered and
dissolved in a minimal amount of ethanol. Due to some byproducts produced from the ozonolysis, a sodium bicarbonate solution is used to neutralize any
acids present. The pH is checked to be 6.5 7. A stoichiometric amount of sodium metabisulfite is dissolved in a minimal amount of H2O and then slowly
dripped into the dissolved crude piperonal solution, resulting in a precipitation of bisulfite adduct. No initial recrystallization is necessary, and
using the bisulfite adduct has slightly increased the final yields, which were likely affected by the recrystallization processes. As previously
mentioned, the automation of the ozonolysis process, combined with the elimination of the distillation step after completion, has significantly
streamlined the procedure. In a day and a half (probably closer to 3/4), I was able to produce 21g of purified piperonal using only two consumer-grade
1g/hr ozone generators. I did not continuously operate the generators and merely reloaded the reaction vessel at my convenience (once TLC had shown
completion)(turned off when reaction was finished). The generators did not utilize an oxygen concentrator, as I am currently in the process of
procuring one. |
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clearly_not_atara
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I figured that potassium piperinate in water was the way to go for this. Previous work found the potassium salt to be much more soluble than the
sodium salt. And water, unlike organic solvents, does not have fire or explosion risk with ozone. The remaining concern was foam. That seems to be a
minor issue if at all. Nice find!
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Texium
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Please post a link and credit the original poster
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underground
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I can not, the forum is dead. Those are copy paste messages from a pdf file. The procedure is legit and true, It involves photos from the set up and
the final product. You got now the information, you just have to try it. Ethanol was the best solvent since no peroxide where formed, while using iso
there where a few peroxides so stick with ethanol.
Those first 3 quotes i posted are the most important from the whole topic
[Edited on 4-4-2026 by underground]
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Texium
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I’m not questioning the validity of the procedure, but you should still say what forum it was and the username of the original poster. It’s just
common decency and good practice to credit a source of information, and seems weird to not do that.
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AvBaeyer
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Here ya go:
https://chemistry.mdma.ch/vespiary/Piperonal%20successfully%...
It took about 10 seconds to find this. Should not have been too hard for the OP.
AvB
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underground
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Thanks for posting it AvBayer, you got me out of any difficult situation 
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Mush
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This is the 44 post long archived pdf, now stands at 77 posts.
Btw this post is super scientific discussion , tonnes of references mentioned .
I would like to point out a concern regarding to this reaction from other members of the vesp forum (think it is in the pdf as well). Namely the
hydrogen peroxyde , ozonides, hydroperoxyacetals unknown/ leftover concentartion, which could potentially blow up in someones face in large or even
prep scale, during workup .
I did not happen in the procedure , had been repeated numerus times with success, but it does not mean a disaster will not happen.
Everybody should start with the original piperine-ozone paper from the forensic team, alkene ozonolysis is a dangerous reaction. Read as much as
possibe of this reaction an precautions, before attempting anything.
Usually this type of reaction is run at below -70 C , a mixture of solvent (usually aceton) and water , not just in ice bath and water medium.
Also, there are different workup methods.
[Edited on 6-4-2026 by Mush]
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beeology
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https://www.thevespiary.org/talk/index.php/topic,21303.0.htm...
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