Hey guys,

I used to have some problems with M.HCl re-x in the past, so I rather sticked to the ipa/acetone/mek washes + activated charcoal purification in my extractions.

But recently I finished with not as white M.HCl as would be required and rather than another wash or charcoal round decided to try re-x again. So I decided to use hot methanol in minimal amount to dissolve mescaline and added quite a lot of hot dry ipa/mek. Boiled for some time to evap the methanol and put into the freezer for 12h. Mescaline crystallized on the botton and was filtered out. Remaining ipa/mek was stored on the shelf at room temp for 24h.
To my surprise there was quite significant crystallization in the erlenmeyer flask with the ipa/mek, regardless of the higher room temp, the difference between the room temp and the freezer was >40C.
These crystals were much more pure than crystals obained by crystallization in the freezer.

So my question is - does anyone have an explanation? I believed everything should crystallize when the solution is cold. Why is it crystallizing even when most of the mescaline is already out of the solution and the temperature rises by 40C?
I know that while re-x'ing dmt from heptane, when I remove it from the freezer after 12h, filter out and put the heptane into the freezer again, there is some residual crystallization, but this is because of the low temps of the freezer. If the heptane is left in room temp, there is no any crystallization, as expected.

I find that this happens a lot with crystallizing of organic amine salts in alcohols. It cleaner because any of the crap drops out with the first crystallization, so the second crop collected is usually extremely pure.

Crystallization just takes time, there are more H-bonding interactions in polar solvents with salts so the dissolved salts can be more meta-stable, and crystallization process slower.

As well, when you get everything dissolved and place in the freezer, it can become super saturated, again, reaching a meta-stable state. So you might filter off the first crop, but the second crop only crystallizes because you now disturbed the liquid, giving it the required energy boost to crystallize. Sometimes this process happens very fast and suddenly, or slow and it takes a day or two.

When i do these recrystallizations, I don't use with the freezer straight away, you get better crystals when the process is slower. For mescaline as well, having dry dry anhydrous solvents isn't necessary, I get better crystals if I add a little water. I use 80% ethanol, I find it is better than using anhydrous ethanol. I let this crystallize overnight first at room temperature, then I place it in the freezer to collect the rest. Even then, its better to wait at least 48 hours.

Well, this goes behind my knowledge. But I can accept it and next time simply rather leave it for few days, maybe with slower cooling.

Last time I tried to re-x from mek with slow addition of water, but mescaline didn't want to dissolve even when I added quite a lot of water. I lost some product due to my mistake, so couldn't check the weight of the final product and expected re-x loss.
I was afraid that adding so much water led to some loss because mescaline stayed dissolved in the solution and didn't crash out. So decided I won't use this method anymore.
So this is why now I chose anhydrous methanol.
Are you sure that the water is not causing unecessary losses? Unlike methanol it stays in the solution because of higher boil temp.

yes if you use too much water, then you have losses since some will remain in solution.

I use sulfate salt instead of HCl, since it's less water loving, and in even 50% ethanol water the amount that remains in solution is negligible, but still I find that's a bit too much water, and 80% ethanol works perfect. Can always evap and then re-extract the water solution if necessary to recover some, sometimes I will do this with all my combined crude extracts to clean it up.

I wouldn't bother using MEK at all, its not very miscible with water at all so I can imagine why that went badly. I would stick to alcohols and water. Ethanol and isopropanol are best. Methanol is ok for getting everything into solution, then diluting with something like isopropanol, but not great as a re-crystallization solvent in this case. It keeps salts in solution easily, so you will definitely see losses as well if you use too much methanol, but at least it is easier to evap to recover the crude.

Thanks Mindlusion for your responses.

M.sulfate would make it much easier. But I have to stick to M.HCl due to higher water solubility which is important for rectal ROA.

I thought I would just dissolve M.HCl in hot methanol, then add hot mek and ipa because they have higher boiling points and then evaporated the methanol, so only mek and ipa would stay in the solution. M.HCl is not very soluble in these when cold, so it would crystallize when put into freezer leaving the impurities in mek/ipa. Actually this would be the same like just washing mescaline with ipa/mek but including breaking the crystal lattice.

What is not clear is whether boiling of whole solution of let's say 30ml of methanol, 250ml of ipa and 250ml of mek and its evaporation to about 400ml would mean there is no methanol, as it was supposed to evaporate first because of its low boiling temp compared to ipa and mek.
If so, then the losses would be minimal, as M.HCl cound not hide anywhere and would have to crystallize.
But if my assumption was wrong and methanol is still within the solution, then there is some mescaline.
Could you please assess this idea? Do you think the methanol was evaporated?

Its possible if the solvent system forms an azeotrope, then a significant amount of the methanol might be leftover. Mecscaline HCl dissolves easily in boiling isopropanol, i would skip the methanol and do that instead if you are worried. There will always be a bit of mescaline left in the solution, sometimes more than you would imagine even with alcohol solvents. I just save all of the motherliquor from different batches and then recover whats left in the future.

If I remember right, I was trying re-x of M.HCl with boiling ipa only and had problem to dissolve everything, it required quite a lot of ipa. Maybe it just takes too long and I didn't want to wait, as any longer boiling of any solvent is difficult in my environment (no lab and my wife hates any solvent vapors).

I always keep all the solvents till the end so if the loss is too high, I can recover the medicine. Sometimes I just evaporate it to see what remains. And sometimes I even bioassay that
If the loss is small enough, I just let it go, never trying to recover the last bits.

Nonetheless, I have sampled all products of individual purification steps and will send them for analysis, so the results will show whether re-x is worth the work...

Mindlusion, thanks again for your input!

Yes, it does use quite a bit IPA, even more with sulfate, but not as much with HCl. But thats why I use ethanol its the goldilocks alcohol hehe