Pepper to Piperonal

[dcook]

Materials & Apparatus

Black pepper: supermarket, grocery store
Ethanol: distillation (http://chemistry.about.com/od/chemistryhowtoguide/ht/ethanol.htm)
Potassium hydroxide: online
Acetone: hardware store
Distilled water: supermarket, grocery store
Hydrochloric acid: hardware, pool supplies store
Potassium permanganate: hardware store

Condensor
Boiling flask
...



Procedure

black pepper → piperine:

Place 15g of ground black pepper into a 250mL round-bottomed flask.
Add 150mL of 95% ethanol.
Heat at reflux for ≥2 hours.
Filter the mixture.
Concentrate the filtrate to a volume of 10-15mL by simple distillation.
Place a 10mL solution of 1mL KOH to 9mL of 95% ethanol into a 125mL Erlenmeyer flask.
Add the concentrated pepper extract to the Erlenmeyer flask.
Heat the resulting solution and add water dropwise.
A yellow precipitate forms. Add wateruntil no more solid appears to form.
Allow the mixture to stand atleast overnight.
Collect the solid by filtration.
Recrystallize it with 10-20mL of acetone.

piperine → piperic acid:

Place 1g of piperine and 10mL of a 10% solution of KOH in 95% ethanol in a 50mL round-bottomed flask.
Attach a condenser and heat at reflux for 90min.
Then attach the flask to an apparatus suitable for distillation under reduced pressure.
Using an aspirator, distill until dry and collect the distillate in an ice cooled receiver flask.
Scrape the residue into a 125mL erlenmeyer flask, use water to rinse material clinging to the sides of the round-bottomed flask.
Suspend the residue in a total volume of about 50mL of water, heat over a steam bath.
Then acidify, in the fume hood, with hydrochloric acid. occasionally swirl the erlenmeyer flask.
Collect the voluminous yellow precipitate of piperic acid by suction filtration.
Wash with cold water and recrystallize from hot ethanol.

piperic acid → piperonal:

Add potassium permanganate to the piperic acid?

[dcook]

Hey, I'm just a lowly college student that has taken a few ogranic chemistry classes. I've been gathering info on how to go from black pepper to piperonal. The above post is what I've got so far.

Still don't have any of the aparatus needed listed.

I haven't found a documented method on how to prepare piperonal from piperic acid.

Lastly, the ethanol and potassium hydroxide are dangerous goods. But other than that, everything else can be super easily bought at any local store.

[Von Bass]

Well, I can verify the first stage as being fairly easy and successful. Don't worry about keeping the reflux for exactly two hours, just over two hours, as long as there's still plenty of solvent in there you can push another hour.

I would imagine KOH could be easily swapped for NaOH, which is yes fairly nasty solid, but its fairly easy to work with safely; rubber gloves, don't fucking spill any etc :) Ethanol is safe, if an expensive solvent to acquire, but thats generally due to alcohol taxes.

I would be interested to hear how any stages of conversion go and what the yields are like.

[stateofhack]

Well, I can verify the first stage as being fairly easy and successful. Don't worry about keeping the reflux for exactly two hours, just over two hours, as long as there's still plenty of solvent in there you can push another hour.

I would imagine KOH could be easily swapped for NaOH, which is yes fairly nasty solid, but its fairly easy to work with safely; rubber gloves, don't fucking spill any etc :) Ethanol is safe, if an expensive solvent to acquire, but thats generally due to alcohol taxes.

I would be interested to hear how any stages of conversion go and what the yields are like.

The last stage gives you HARDLY anything workable...:(

[dcook]

Well, I can verify the first stage as being fairly easy and successful.

Just to make sure. Step 3 "Heat at reflux for 2 hours." is not for distilation, but for speeding up the reaction so I can run it at high heat and not worry about the stuff evaporating, correct?

Step 4 mentions vacuum filtration. Can't I just use gravity filtration? I don't have a filtration flask, but I guess I should purchase one.

Another problem with my equipment is that I only have a basic hot plate. So stiring becomes difficult. Another much needed investment I suppose, bumping is not cool, especially with cheap glassware. Heh.


The last stage gives you HARDLY anything workable...:(

Dang. Really? You're referring to the piperic acid to piperonal conversion, right? How much reagant were you using?

[Von Bass]

Just to make sure. Step 3 "Heat at reflux for 2 hours." is not for distilation, but for speeding up the reaction so I can run it at high heat and not worry about the stuff evaporating, correct?

Yarp, standard reflux setup.

Step 4 mentions vacuum filtration. Can't I just use gravity filtration? I don't have a filtration flask, but I guess I should purchase one.

Yarp, I'm pretty sure I did so without vacuum filtration.

Another problem with my equipment is that I only have a basic hot plate. So stiring becomes difficult. Another much needed investment I suppose, bumping is not cool, especially with cheap glassware. Heh.


Wouldn't worry about it, fuckloads of black pepper granules will work as enough of an antibumping agent, I did the extraction without a magnetic stirrer, just don't boil it too vigorously.

[dcook]

Thanks for the info Von, I've edited the original post accordingly.

Yeah, as for the ethanol, seems like distilling your own is the easiest way to go about things.

[purewhitepanda]

Pepper to Piperonal = SHIT,WAT THE FUCK. I'VE BEEN SITTING HERE WATCHING AND I DON[T SEE SHIT. BROKE ASS FUCKER'S. I BET MORE ON POKER THAN THIS BROKE ASS BROKE/BLOW ME UP SHIT.

[Aperson444]

Are you sure denat. ethanol with only methanol would not work?

Is there a more "ghetto" way to reflux? I have an Ahlinn condenser for refulxing, but no adapters, thermometers, valves or shit. Just some flasks. Any way to make this? By the way, the narrow end is chipped a bit.

[Fra]

Even if you could do so, you would still need kgs of pepper to start with, lot of reagents/solvents and big glassware. While piperonal is hard if not impossible to buy, there are product which are cheap and contains lots of easy usable piperonal

[nshanin]

It's quite easy to synthesize piperonal, you should try that instead of doing a mega-extraction.

[Ford]

It's quite easy to synthesize piperonal, you should try that instead of doing a mega-extraction.

Yeah. Just made a thread on that. Or buy piperine/bioperine.

...

Anyways, did a fair bit of research on this method over the past couple years with moderate success. Here's an zip of most of my notes and refs, maybe somebody'll find it useful: http://www.zshare.net/download/6302381912893464/

[dcook]

Anyways, did a fair bit of research on this method over the past couple years with moderate success. Here's an zip of most of my notes and refs, maybe somebody'll find it useful: http://www.zshare.net/download/6302381912893464/

I most certainly do. Thanks a ton!

[eesakiwi]

SwIms done all this extraction. Not the KmNO4 part though. (well not properly)

SwIm used 500 gms (one Pound - Lb) of ground pepper. & Meths (denatured Ethanol)

Puts that in to a clean plastic coke bottle, adds meths untill the pepper is covered.
Puts the cap back on & chucks it in the microwave untill its HOT.
Pulls bottle back out, stands it up, gives it a good Tap so the pepper goes to the bottom & lets the meths rise up, pours the meths off.

Do the several times, you will probably need about 1-1/2 litres of meths for 1 Lb of pepper.

Filter the solvent/pepper extract.
Boil off a lot of the meths, then cool it down, then add water dropwise untill the crystals start to form etc etc.
You will get crystals & a grey/green/brown gloop.

You can extract it with Acetone & add Pet ether to clean the crystals up.

Then do the Potassium hydroxide part.

[stateofhack]

I have done the piperic acid → piperonal using KMnO4 and chromates and have gotten only shit :(

piperine → piperic acid even this step has given me loads of tar goey shit..this is not the way to go on about it people :(

[missingno]

perhaps piperine may go through oxidation to piperonal rather than having to prepare the piperic acid?
if the yeilds are good then thier wouldnt be any use for the preperation of piperic acid...

[eesakiwi]

I have done the piperic acid → piperonal using KMnO4 and chromates and have gotten only shit :(

piperine → piperic acid even this step has given me loads of tar goey shit..this is not the way to go on about it people :(

There is a tar/gooey shit but the actual crystals of piperic acid are seperate from the tar.
I'm not sure as how to explain it as I did it a long time ago.

Theres also the option of adding the Koh to the meths in the first stage, before extracting the shit out of the pepper. I think it uses more Koh though.

I have done the Potassium permanganate thing, but 'by eye & hand'.
Not using proper stirrers & measuring flasks etc.

I think the Bromine route sounds more feasable, to me anyway.

[stateofhack]

There is a tar/gooey shit but the actual crystals of piperic acid are seperate from the tar.
I'm not sure as how to explain it as I did it a long time ago.


Intresting, last time there was so much crap that i didn't even bother, might give it another shot! Can you expand a little more on color/apperance and what you did?

Thanks!

[idontlie]

Note to self:
Take top off bottle before inserting in microwave.

=) with love from stupid

[idontlie]

Puts the cap back on & chucks it in the microwave untill its HOT.


I don't believe you. Even 1 minute capped in the microwave in a plastic soda 2liter causes the bottle to explode.

The bottom will expand out under heat then pop the top when expansion is stopped spraying hot liquid and pepper everywhere. This will stain metal, paint, wood, ect with a yellowish tint. The yellowish tint is best removed using a rag damp with denat alcohol on wood and wall and acetone in the microwave.

I would suggest this in a nice stove top coffee pot, the one with out the metal ring at the base. So much easier to pour into a filter.

Something along the lines of 1g pepper : 15ml alcohol nuke for 1 minute wait a minute nuke it again (to prevent wild boiling). Pour into filter over glass baking dish (6"x6" clear glass) while still warm. Add ~50ml of fresh alcohol into pot. Swirl to pull the yellow residue off the sides and pour into filter. This does leave a heavy pepper smell to the entire building, fyi.

Two minutes are what is documented as the aprox. 100% extraction, regardless of solvent. Past 2minutes you start to pull other less desirables from the pepper

The loss from an open pot was acceptable to me if its not to you damp rag the top of it. But meh. Pepper is 30 cents per ounce or less. A liter of alcohol is ~$4...

This is traditional EtOH but MeOH is talked about a lot here. (I'm guessing a Rhodium thing.) DCM is the ideal extraction medium but it is ~$10/Liter. Or twice as expensive as cheap ol' Denat. Alcohol.

[eesakiwi]

I don't believe you. Even 1 minute capped in the microwave in a plastic soda 2liter causes the bottle to explode.

The bottom will expand out under heat then pop the top when expansion is stopped spraying hot liquid and pepper everywhere. This will stain metal, paint, wood, ect with a yellowish tint. The yellowish tint is best removed using a rag damp with denat alcohol on wood and wall and acetone in the microwave.
into pot.

This does leave a heavy pepper smell to the entire building, fyi.

Two minutes are what is documented as the aprox. 100% extraction, regardless of solvent. Past 2minutes you start to pull other less desirables from the pepper

The loss from an open pot was acceptable to me if its not to you damp rag the top of it. But meh. Pepper is 30 cents per ounce or less. A liter of alcohol is ~$4...

This is traditional EtOH but MeOH is talked about a lot here. (I'm guessing a Rhodium thing.) DCM is the ideal extraction medium but it is ~$10/Liter. Or twice as expensive as cheap ol' Denat. Alcohol.
--------------

Oh shit. !

I forgot to mention squeezing the bottle so theres not much air in it before microwaving.
Glad you spotted that...

I did have all that happen though, the microwave is unusable for food cooking now too.
Last time a bottle exploded & it musta bumped the microwave a bit hard & it stopped working, mighta been the fuse breaking.

Hot spots appear in the solventpepper mix, so microwave in small bursts & take out & shake often.
You can hear as the bottle expands & pops out the dints in the bottle.
----------

I used DCM once & found it pulled out a lot more rubbish than usual & considering the cost, its wastefull.

Alcohol was best & Pet ether only extracts a lot less per Litre than alcohol.
Acetone & Pet ether is best used for recrystalization.
Dissolve in Acetone & add Pet ether untill it gets slighty cloudy, than add a little more Acetone, then let it cool down.
-----------
When you add water to the alcohol/pepper solution it will get milky a little bit as the waters added.
Slow down the water addition & the shit will come out first.

Then decant it off the shit as soon as you see 'the crystals' sparkling in the alcohol/pepper/water mix.
( I guess you could add the Koh now, then heat it up for a while so it reacts.)
Then add more cold water to get the light yellow/brown crystals.

or. Crystalize out the crystals, dissolve in alcohol & work out the 'Koh amount', add that, then heat to react, add cold water to get the crystals.
Recrystalize from Acetone/Pet ether.
----------------

The 'gooey shit'.
I extracted with pure Pet ether to get some more clean crystals from it.
It uses lots of Pet ether to do this but the product is clean.
Its good if you can recycle the Pet ether out.

The gooey shit just gets darker & more solid untill it turns into some sort of solid resin/varnish like shit.

I dissolved it in alcohol & poured it into some termite/bug mix I had made up & sprayed it onto some wood I was treating for termites etc.
Some I poured around the fence area to stop dogs from shitting there.
Only sorta worked.

[idontlie]

--------------

Oh shit. !

I forgot to mention squeezing the bottle so theres not much air in it before microwaving.
Glad you spotted that...

I did have all that happen though, the microwave is unusable for food cooking now too.
Last time a bottle exploded & it musta bumped the microwave a bit hard & it stopped working, mighta been the fuse breaking.

Hot spots appear in the solventpepper mix, so microwave in small bursts & take out & shake often.
You can hear as the bottle expands & pops out the dints in the bottle.



So they sell these really really cool baby bottles that are microwave safe. They are really awesome and the little nipple at the top is really cool in the part where it keeps the pressure from building up to high. Also when you figure out they are small and the 4 you put in at once is stupid you can go back to the store and look at the plastic microwave safe 1/2 gallon containers. You can even go online and pull up the reactivity data for the material. You will find that these are perfect. and they dont have the nasty habbit of growing on you until the a seam or cap busts.


----------

I used DCM once & found it pulled out a lot more rubbish than usual & considering the cost, its wastefull.

Alcohol was best & Pet ether only extracts a lot less per Litre than alcohol.
Acetone & Pet ether is best used for recrystalization.
Dissolve in Acetone & add Pet ether untill it gets slighty cloudy, than add a little more Acetone, then let it cool down.



You will find per cost Denat EtOH is the most bang for the buck. Thank you for the tip.


-----------
When you add water to the alcohol/pepper solution it will get milky a little bit as the waters added.
Slow down the water addition & the shit will come out first.

Then decant it off the shit as soon as you see 'the crystals' sparkling in the alcohol/pepper/water mix.
( I guess you could add the Koh now, then heat it up for a while so it reacts.)
Then add more cold water to get the light yellow/brown crystals.

or. Crystalize out the crystals, dissolve in alcohol & work out the 'Koh amount', add that, then heat to react, add cold water to get the crystals.
Recrystalize from Acetone/Pet ether.
----------------


We are all impatient but you may find that if you spend the time to get the amounts correct you can achieve about a 10% greater yield. This isn't that big a deal when only working with a pound or so but when you are spending the day experimenting with your microwaves different settings.

Thank you for that.

[eesakiwi]

Yeah its damn fun doing it.

Everything stinks of pepper & when I went to sprinkle some on my baked beans last night, the first thing I thought about was the crystal Piperine..

The piperine mix glows under UV light a bit.
A dark yellow x2/green x3/brown x1 shade.
With the lights off you can see where you spilt it on the bench & where it drips down the side of beakers & stuff.

Thats handy as you get to see how much piperine is left in the pepper grounds.
The LED UV light was $3 at a kids toys area of a mall. Spy pen or something, its built into a UV felt pen for secret writing.

By using the plastic drink bottle in the microwave (its inside glows under UV light).
I could plug the neck of it with cotton wool & screw on a 'pop top' drinking bottle cap.
Then just squeeze the bottle & it filters the solvent mix out of the grounds.
3 washes took out most of the dissolvable stuff.