Kavion123
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CWE of Piperidine
Can I perform a cold water extraction to grab piperidine from black pepper? I know piperine, the alkaloid, is not so water-soluble at 278K.
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Bert
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12-1-2015 at 19:33 |
Praxichys
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The point of extracting using a nonpolar solvent is so that most of the water soluble garbage is left behind. You might be able to extract
something from pepper with cold water, but it will probably be a bunch of starchy, salty crap.
An acid/base extraction with would be far better. Soak or macerate the pepper in weak acid to generate the highly soluble salt of the alkaloids, then
filter. Add a base until the solution is basic, which reduces the water solubility of the alkaloid. Extract the solution a few times with something
nonpolar and volitile. Take your pick - xylenes, toluene, lighter fluid, camp fuel, chloroform, dichloromethane, ethyl acetate, diethyl ether, light
naphtha...
Dry off the solvent and you are left with alkaloids, because of their ability to change solubility drastically based on pH.
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Kavion123
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Quote: Originally posted by Praxichys  | The point of extracting using a nonpolar solvent is so that most of the water soluble garbage is left behind. You might be able to extract
something from pepper with cold water, but it will probably be a bunch of starchy, salty crap.
An acid/base extraction with would be far better. Soak or macerate the pepper in weak acid to generate the highly soluble salt of the alkaloids, then
filter. Add a base until the solution is basic, which reduces the water solubility of the alkaloid. Extract the solution a few times with something
nonpolar and volitile. Take your pick - xylenes, toluene, lighter fluid, camp fuel, chloroform, dichloromethane, ethyl acetate, diethyl ether, light
naphtha...
Dry off the solvent and you are left with alkaloids, because of their ability to change solubility drastically based on pH. |
Thank you.
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Nicodem
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Piperidine is not contained in relevant amounts in pepper (Duke's phytochemical database lists it as a component, but does not give the content). The
only thing easily extractable from pepper is piperine.
| Quote: Originally posted by Praxichys | | An acid/base extraction with would be far better. Soak or macerate the pepper in weak acid to generate the highly soluble salt of the alkaloids, then
filter. |
Piperidine partitions very well into water, basic or not, so that an acid/base extraction would not be particularly successful.
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unionised
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The stuff that makes pepper "peppery" is piperine.
Since the nitrogen atom in piperine is in an amide, rather than an amine, it's not going to change solubility very much with pH unless you make the
conditions so drastic they hydrolyse it.
A "classic" alkaloid extraction won't work for piperine.
It barely works for piperidine (because it's very water soluble, even as the free base) and there's not much of it there anyway.
What are you actually trying to do?
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Bot0nist
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I was able to extract piperine from black pepper here using refluxing isopropyl and a bit of workup.
Piperine from black peppercorn, 91% isopropyl alcohol.
[Edited on 14-1-2015 by Bot0nist]
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squeezix
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I guess I’ ll dig up this old thread rather than post a new topic. Firstly, the subject here is piperidine, not piperine even
though that’s where OP obtained said piperidine. I have questions and I have been searching for the answer for a year now. When reducing pyridine in
ethanol with sodium to obtain piperidine, we are left with our piperidine in a water/ethanol solution. The most efficient way to isolate the
piperidine will be conversion to the hydrochloride salt.
Many reactions use the free base of piperidine and few call for piperidine hcl. The issue I’m having is that the free base is so freely miscible
with water, that basifying using an NaOh solution brings me right back to the same problem. Too much fucking water. The reactions I want to do with
piperidine tend to be anhydrous.
Does anybody out here have experience with getting piperidine base out of water? What pH renders it insoluble in water or at least more soluble in
say, ether, which dries off quickly. I’m banging my head against a wall on a procedure I know I’m doing correctly and I’ve finally figured out
that my piperidine is anything but anhydrous.
Any links or literature would be greatly appreciated. I rarely ask to be spoon fed, mainly because I believe it a hindrance to learning, but my
obsession to purify this substance will continue to burn valuable time when I know there must be a simple-to-intermediate procedure out there.
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Fery
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I do not know whether my info could be useful for piperidine, but pyrrolidine which is 1 carbon smaller molecule could be obtained anhydrous by
treating with solid NaOH.
https://www.sciencemadness.org/whisper/viewthread.php?tid=64...
you can very likely distill off a lot of water from hydrochloride
then neutralize with conc. sol. NaOH or maybe with solid NaOH?
then separate and discard solid NaCl
then distill out a lot of H2O using efficient column?
then treat with solid NaOH and distill out pyrrolidine?
the problem with the last 2 steps could be the presence of NaOH which will raise b.p. of H2O which is undesirable, b.p. of piperidine 106 C (this is
not problem for pyrrolidine as its b.p. 87 C is lower than b.p. of H2O)
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Fantasma4500
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it may be possible to defat the pepper first up by boiling it with NaOH solution, then the dried out pepper can be extracted with ethanol. ive had
good success follow nile red's video on piperine as well, later i had a failure where the piperine was impossible to filter off though
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