Sciencemadness Discussion Board

Help with scalating a synthesis please

TuRazika69 - 15-9-2019 at 19:51

I wanna prepare piperonal / heliotropine from piperinic acid using chemplayer's video method

The problem is that he uses very little reagents and obtain only 0,5g of piperonal

How can I scale up the synthesis to get for example, about 100g of heliotropine / piperonal??

The synthesis video is here

I'm a bit new in this subject so I don't wanna screw up and ask for help) I know some stoichometry but for example I Dont know ho to calculate the solvents needed for a bigger reaction

Best regards and I hope with your help I can learn a lot!!!

Best regards!!!

ihillside - 15-9-2019 at 19:59

It looks really great

PirateDocBrown - 16-9-2019 at 00:26

What's your source of piperinic acid?

It should scale up directly, if you have the starting reagent.

TuRazika69 - 16-9-2019 at 06:42

My source is piperinic acid made from piperine.

Best regards!

So I for example, multiply per 50 the reagents that ChemPlayer used and that's it? And for the solvents like DCM?

Best regards and thank you a lot! :)

Sigmatropic - 16-9-2019 at 09:59

I would be most concerned about the reaction itself and figuring out when it's finished.

With very rapid reactions, mixing rate turns into a variable and this is usually reduced on scale up. Odds are the reaction is not finished in two minutes and substantially more over-reaction happens in some parts of the reaction vessel whereas unreacted material remains in other parts.

Also this 200 mL/g of starting material reaction volume is going to break you up on scale up. For 50 g thats 10 liters, you have to filter and extraction that very same volume. Do you have equipment that size?

TGSpecialist1 - 16-9-2019 at 12:20

For a larger scale it would be better to use a different reaction, either ozonolysis or using hydrogen peroxide with sodium tungstate and bicarbonate instead of KMnO4 and using much more periodate, preferably sodium periodate. It would also incerase yield and made less water nesscesary.

PirateDocBrown - 16-9-2019 at 20:05

Where are you getting large quantities of piperine?

chemplayer... - 20-9-2019 at 21:20

The steps to get to piperinic acid from peppercorns should scale up ok, but there are no guarantees that the oxidation step will work in the same way using different quantities and volumes - for a few different reasons but a) because oxidations are exothermic and changing the volume and quantity of reagents changes things (larger volume, less surface area relatively for heat to come out), and b) as stated above the mixing rate will change. It's a delicate reaction.

You don't need a lot of heliotropin to enjoy the aroma though...

PirateDocBrown - 21-9-2019 at 00:57

Doing oxidative alkene cleavage like this can be quite tricky.

If your reagent is too strong an oxidizer, the aldehydes you want to end up with becoming carboxylic acids.

I saw chemplayer's videos for this reaction, where a mixture of periodate and permanganate were used, and then suddenly stopped with a reagent that quenched the oxidizers. Quite impressive.

I have done oxidative cleavage myself in this manner with permanganate, but my target was the carboxylic acid, and that's exactly what I got.

If my target was an aldehyde, well, our lab had an ozone generator. Very effective, but likely outside the range of a home chemist.

Now, it's entirely possible, and probably easier to just go ahead to the carboxylate, and then reduce to the aldehyde, as an additional step. The downside here is that it's easy to overshoot the reduction as well, and you wind up with an alcohol. And reducing reagents are usually harder to come by than oxidizers, especially OTC.

[Edited on 9/21/19 by PirateDocBrown]

PirateDocBrown - 21-9-2019 at 01:02

OP, do report your results, I'd love to see what route you take!

TuRazika69 - 21-9-2019 at 20:28

I will use the method and I'll try scaling it up but one more question if for the reaction I will follow from piperinic acid to piperonal he uses to extract 200mL per gram of starting piperinic acid if I will start let's say, with 100g, do I need to scañate up also the solvents for extracting etc?

Sorry about my idiotness it's the first time I will scañate anything I only did always straight follow synthesis routes and I'm totally autodidactical

Best regards and thank you everyone, hoping youre had a good week!!! :) "

Steam - 22-9-2019 at 16:14

Looks really great! I am definitely excited to see what comes out of this! Great work!

arkoma - 8-11-2019 at 18:45

Quote: Originally posted by chemplayer...  

You don't need a lot of heliotropin to enjoy the aroma though...


extraction of piperine is tickier than it looks/sounds. you best practice on a smaller amount. trust me on that one. gone through pounds of pepper over the years.