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Precipitating cocaine HCL from Freebase (purification question)

I Eat Pho

I Eat Pho

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Hi,

I've read all of the related posts on this topic as well as done my own independent research. I've read all of Le Junk's posts and all posts related to precipitating HCL from base but my question is still unanswered.

I am interested in using the method of precipitating HCL from base that does not require diethyl ether (instead using acetone, methanol, hcl). My question is this:

Since there are two ways to start precipitation..
a) Getting the ph down to 5.5 which is the ph that cocaine hcl will precipitate out
b) Using the proper stoichiometric ratios of hcl and acetone

- Are they both equally effective/efficient?
- If using the ph method, does it matter what percentage your hcl solution is prior to adding it to the base since you are just getting it to the ph?

Thanks.

Also, is anyone familiar with gassing hcl? I am aware that it is much more efficient and I understand the process of gassing but I can't find any info on how much gas would need to pass through without going overboard and destroying my alkaloids.

I appreciate any help.
 
You won't destroy any cocaine in (relatively) anhydrous solvents. HCl gas is produced by dropping conc. H2SO4 onto NaCl or NH4Cl, which was moistened with some HCl before, employing a Kipp's apparatus. See Vogel's for details and please don't hurt yourself.
You do not need to calculate the exact amount of HCl required; you won't be able anyway to exactly measure out the required amount. Simply dissolve the freebase in a suitable solvent (diethylether, acetone, dioxane, ...) and bubble HCl-gas through the solution until no more precipitate is produced. Filter off insolubles (=cocaine-HCl), wash once or twice with a little (anhydrous) amount of the used solvent and you're done.

Btw, the pH is only valid in aqueous systems and has no meaning when you plan to produce a hydrochloride from an organic solvent.
 
Hyperthesis, thank you very much for the info. Just to be clear, I can in theory dissolve the base in anhydrous acetone and just bubble HCl gas through the solvent until no more is precipitated without worry about "overdoing it" with the HCl gas and ruining my product?

Thanks for clearing up the pH thing. So only when the HCl is in an aqueous solution does the pH matter... gotcha.

One more question, is stirring necessary when gassing? Or does the force of the gas bubbling act as the stirring motion.

Thanks
 
I Eat Pho said:
Hyperthesis, thank you very much for the info. Just to be clear, I can in theory dissolve the base in anhydrous acetone and just bubble HCl gas through the solvent until no more is precipitated without worry about "overdoing it" with the HCl gas and ruining my product?

Thanks for clearing up the pH thing. So only when the HCl is in an aqueous solution does the pH matter... gotcha.

One more question, is stirring necessary when gassing? Or does the force of the gas bubbling act as the stirring motion.

Thanks
Click to expand...

No, but the more contact, the more mixing, the merrier. So if you can stir it, do so, but thinking about it, i can't think of a nice way to stir it at home.

There are people who spend their entire careers designing more efficient ways to bubble a gaseous reactant through a liquid one.
 
What if I just use the hose that I'm bubbling hcl gas through to stir it? It's somewhat rigid and is already in the solution? Seems simple enough which makes me think it's probably a stupid idea.
 
question

What if a few drops of 10% hcl solution are poured over the base until it's all dissolved. If that is evaporated, there's hcl cocaine left right? I'm asking cause I can't get acetone easily:D
 
jammon said:
What if a few drops of 10% hcl solution are poured over the base until it's all dissolved. If that is evaporated, there's hcl cocaine left right? I'm asking cause I can't get acetone easily:D
Click to expand...

That's a really crude way to do this, but it should work. I'd put the rocks in a small amount of water, then add HCl solution dropwise until it was dissolved (you don't want to add more than needed. HCl fumes are no fun to breath, and any HCl in excess of what's needed will be released when you evaporate the solvent), and then evaporate the liquid.

I've never tried this, though - I'm not a stimulant man.
 
10% HCl will hydrolise the cocaine I think.


If you can't find acetone, one of the simplest solvents around, you have no place dabbling in chemistry.
 
^Correct! The trick with anhydrous solvents is that there is no water that would enable hydrolysis of cocaine's ester-moiety. Both concentrated (~36%) and 10% HCl contain water, which will lead to (partial) hydrolysis of the precious coke. In other words: You will lose at least some, if not all (depending on your handling speed/skills) cocaine in this procedure.

I'm sure places like ScienceMadness provide detailed instructions where to get from resp. how to dry acetone properly with OTC material. This isn't actually illegal anywhere in the civilized world.
 
to be honest, HCl will not hydrolyze an ester unless it is particularly unstable, you use incredibly high concentration, or you heat the fuck out of it.

by this I mean that the extent of hydrolysis will be extremely small.

HCl is not a particularly useful reagent for simple hydrolysis. if you were doing this from the other POV, you would choose an acid like H2SO4 o H3PO4. they are also strong, but they have better catalytic properties w/r to a hydrolysis reaction.

the point is that you do not need to worry about loosing any cocaine to hydrolysis.

unless you heat your mixture, let it sit for hours, or use "straight" 38% muriatic acid from OSH or wherever....

you should have no concerns about hydrolysis.



the other thing is this:


cocaine does suffer from any appreciable "cut" due to water of hydration. In other words: if you were to crystallize cocaine HCl in the presence of water, you would not be adding much weight to the final product.

in fact, I would be willing to bet that the amount of water in cocaine HCl as water of hydration is extremely small.

I mention this because I am trying to figure out why you are so concerned with crystallizing (salting) the cocaine under anhydrous conditions. Are you concerned that, in the presence of a very small amount of water mixed with the acetone, that you will lose a meaningful amount of your cocaine? Are you concerned that the cocaine will not properly crystallize?

if you are concerned that, say, a 2% water in-acetone mixture will result in a significant loss of cocaine HCl, do not worry.

a mixture of acetone + water does not dissolve the same amount of solute as acetone (individually) + water (individually). The behavior of such mixtures is an always has been an active area of research. you can find plenty of graduate and advanced undergraduate level statistical mechanical treatments of these concepts in a variety of statistical mechanics/thermodynamics/advanced P-chem textbooks. Typically extremely high level mathematics way beyond anything any chemistry student would ever be expected to know at the undergraduate level, regardless of the school... MIT or Chico State... doesnt matter. in fact, harder than moth mathematics and physics students would be expected to be capable of grasping.

here is a clarification of what I just said:

if 98 mL of acetone dissolves X milligrams and 2 mL of water dissolves Y milligrams, so that the total amount dissolved by both solvents (separately) is X+Y milligrams

100 mL mixture composed of 98 mL acetone + 2 mL water DOES NOT, in general, dissolve X+Y... in general you do not know if it is more or less or equal.

in practice you can, at least, qualitatively predict it using a variety of mathematical/computational methods. as far as I know, there is no generic "rule of thumb" or simple guide that allows you to make predictions for all cases.

that being said, I seem to remember being taught that for the variety of simple solvents (solvents with no significant complexing, chelating, coordinating, strong h-bonding, etc.) used in large quantities in industrial and pharmaceutical chemistry, with the majority of the simple Nantes of interest, that the MIXTURES of solvents will almost always dissolve LESS than the separate solvents would dissolve. in other words, according to my little example above, the 100 mL of acetone+water would dissolve LESS THAN X+Y milligrams.

Again, I could be wrong about that. For the life of me I can't remember where I heard it. I can't remember if it was in class, from an adviser, in a text or journal, or just off hand, but I have a distinct memory of being told this. Take it with a grain of salt.
 
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It seems to me that a methyl ester would be much easier to hydrolize in aqueous acidic conditions than you think. Thats why you keep the water out. The benzyl ester on the other hand is much more stable.
 
I don't think it's that easy to hydrolyse either, as long as the acid is dilute and the temperature is cool it should be ok. I'd probably try dissolving the base in acetone (should be available in small quantities from pharmacies, if nowhere else) and adding a solution of concentrated HCl in IPA (good for removing flux after soldering), say 1 part HCl to 5 IPA, until crystallisation is complete.
 
nAON said:
Does it have to be HCl salt though, couldn't you do it with stuff like citrate?
Click to expand...
Guess you can sniff citrate but you should get HCL acid.... you lookin for the hydrochloride (HCl) salt of cocaine dude

Does anyone know how much pure sulfuric acid and water are needed to make a 10% solution?

And the thing about acetone is that it really needs to be anhydrous if you're extracting small amounts of leaves.
I've been told that 1 kg of leaves should be used at least to get a good yield (5 g) and be able to afford losing a little of coke in the end if the tek is not done propertly like in lab conditions.

Physical data of Cocaine from wiki:

Melt. point 98 °C (208 °F)
Boiling point 187 °C (369 °F)
Solubility in water HCl: 1800-2500 mg/mL (20 °C) -> that soluble??

Acetone should be really water-free
I'd use 50 ml of it and dry it with lots of anhydrous potassium carbonate and magnesium sulfate a few seconds before using it
 
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coca leaf

If you dissolve the FB coke in Acetone, you need alcohol besides HCl acid to crystallize the salt out. Always dry the freebase before dissolving it in anhydrous acetone
You can dissolve 1 gr in 15 ml of anhydrous Acetone and add very slowly 1:2 HCL acid/Methanol while stirring.
wait
 
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