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Author: Subject: strangely smelling pepper compound?
Antiswat
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[*] posted on 9-4-2017 at 08:55
strangely smelling pepper compound?


long time ago i played around with crude piperine extract, i think i was trying to purify the piperine using caustic soda
i ended up mixing acetone caustic soda and piperine, when this mixture has been standing around for some time slightly heated a very strangely smelling compound forms, its a bit like pepper and mint at the same time, although very sweet
i have tried making a small bit of piperic acid and it cant be that as of what i can tell

i did a few experiments to figure out what reagents could be causing this, and it seemed to me that all 3 are necessary, as the compound evident by odor wouldnt arise
so the procedure is as following.. a solution of caustic soda and acetone is heated for 24 hours, as low as 40*C will do
a source of piperine is added, its then let heat up a bit more

i tried also neutralizing this mixture with hydrochloric acid but the smell persists, i also noticed that just a tiny bit of this mixed into a lot of air gives even stronger smell, it could be somehow reactive to air?

as i made a bunch of this mix and stashed away i ran distillation on it just today and the liquids i got over were 2 phases, one very oily sticky top layer, very little, less than 1mL, and about 80mL of what seems to be water

of what i understand piperonal should have a nice scent.... but i cant quite agree that i had any strong oxidizer involved in this, and neither alot of oxygen as when i tested out this on a smaller scale it was capped off
of what i remember pepper compounds in general arent liquids but rather soluble salts, and acetone shouldnt seperate into two layers, let alone seem oily, insoluble even
caustic soda is known to react with acetone, giving a brown-red compound, which i indeed got but i dont recall if that red colour was present when i did the smaller tests?



1: flask with 2 phases
http://puu.sh/veDHo.jpg
2: distillation flask showing 3 "phases"
http://puu.sh/veDJ4.jpg

on picture with my remaining liquid that i still need to distill a blackish precipitate is barely visible, the main liquid appears almost orange and there seems to be some sort of solid at the top




~25 drops = 1mL @dH2O viscocity - STP
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https://en.wikipedia.org/wiki/Solubility_table
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[*] posted on 10-4-2017 at 08:22


Quote: Originally posted by Antiswat  
i ended up mixing acetone caustic soda and piperine, when this mixture has been standing around for some time slightly heated a very strangely smelling compound forms, its a bit like pepper and mint at the same time, although very sweet
i have tried making a small bit of piperic acid and it cant be that as of what i can tell

In the presence of NaOH acetone gives mesityl oxide (https://en.wikipedia.org/wiki/Mesityl_oxide) and other products which have a characteristic smell, are you sure that it was not this case?
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Antiswat
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[*] posted on 12-4-2017 at 02:10


yes im quite sure, i of course tested out just NaOH and acetone and it had nowhere near same smell, hardly any smell at all




~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
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wakatutu
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[*] posted on 13-4-2017 at 01:01


are you sure it's not just piperidine?

The description of the smell tends toward piperinic acid, as it smells sort of like magnolia and sort of like mint. With a vaguely...chewing gum-sassafras type odor as well.

Piperidine in the mix will make it reek of nasty. A sort of vaguely pleasant nasty. adding a base in a solvent such as acetone especially followed by standing for some hours or days is a good way to hydrolyze your piperine to its constituents, of which the piperidine is volatile and quite smelly.
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[*] posted on 18-4-2017 at 03:00


Acetone plus an alkali is a reagent that undergoes aldol condensation. When it condenses with itself you get mesityl oxide, as Outer says, and many other condensation products. It also condenses with aromatic aldehydes ... there is a common teaching lab procedure that has it condensing with benzaldehyde ... so there are many possibilities depending on the contents and decomposition products of your pepper extract.
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Antiswat
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[*] posted on 21-4-2017 at 10:17


yes but the smell only comes around after caustic soda has reacted with acetone, ethanol doesnt work out likewise, like swapping acetone with ethanol

i do mean to say ive tried making piperic acid but i didnt find any smell towards that, i was aiming for that it was piperic acid but havent been able to reproduce that smell without reacting NaOH and acetone, simply making piperic acid




~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
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clearly_not_atara
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[*] posted on 21-4-2017 at 11:05


Piperine is a Michael acceptor. In the presence of acetone and NaOH, it forms addition products. The exact product is difficult to determine but it may be c1cc2OCOc2cc1C(CC(=O)C)C=CCC(=O)N3CCCCC3 (1,6-addition) or c1cc2OCOc2cc1C=CC(CC(=O)C)CC(=O)N3CCCCC3 (1,4-addition) or possibly a compound containing two molecules of piperine attached to one molecule of acetone. Additionally a cyclic compound may be produced if 1,6-addition is followed by aldol condensation: c1cc2OCOc2cc1C3C=CC(=C(C)C3)C(=O)N4CCCCC4

It appears that the product has a strong smell. You may have produced a mixture of compounds. It would be interesting to try to purify the reaction products, but if multiple similar compounds are produced, then chromatography may be required.

[Edited on 21-4-2017 by clearly_not_atara]
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Antiswat
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[*] posted on 28-4-2017 at 21:22


guess imma have to settle with that organic chemistry can be hellish, but at times as complex as it may be it can smell pretty nice, but taking joy in appearance or odor is probably quite alien to a chemistry forum anyhow



~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
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