Black compound in MDMA freebase / hydrochloride

[Mr Good Cat]

I'm quite curious about this black compound that appears when hydrochloride heated.


Considering it behaviour (getting black while heated) I always thought it is carbon, but I don't understand how it gets in the solution in such huge amount.


Let's check this guess empirically.


When I do base extraction, I often see the same thing: black base descends below water layer.


For example, I want extract base from 300 gr of hydrochloride. For the beginning I use about 500-600 ml of water. I add around 85 gr of NaOH, and see what I said before; base appears at the bottom.


Now I need to add about 10-15 gr of NaCl per 100 ml of water to move it up.


Let's calculate a bit.


600 ml of water - 600 gr, 600 cm3, density - 1.0 gr/cm3

15 gr of salt x 6 = 90 gr, 41 cm3, density - 2.17 gr/cm3

Final density of this water NaCl solution is 1.07 (I even don't count NaOH leftovers!!!, that shall increase density even more).


It means, density of FB layer shall be around 1.05 gr/cm3.


As people believe, density of base itself is around 0.9.


Let's approach this data for carbon.


Carbon has molar volume 5.3 cm3/mole, that points on density 2.26 gr/cm3.


So, if base - carbon mixture is in proportions 90:10, then density shall be 0.9 * 90% + 2.26 * 10% = 1.04 gr/cm3 - pretty close to the numbers I said before.

Such calculation can explain this phenomenon, but for me it is too much weird to get such huge amount of carbone while product heated. It is also strange for me that carbon mixes with base.

Or, may be, there is some other explanation?

 

[btcboss2022]

Is not carbon it's an impurity of the process very very sticky that normally appears in mixture acid litmus and in this moment is possible to remove it because in alkali mixture it comes liquid.
But I dont know what is it.

 

[Mr Good Cat]

by the way, could it be a route to recover pretty pure hydrochloride from water leftovers? heat them up to 108c, then slowly add them to acetone at RT it in 2 or 3 volumes of acetone to dissolve salt completely, i mean solve it well on stirrer at RT, may be on ice bath. this process will be similar with base acidation in acetone. very similar. i always see acidation in acetone gives better result.
there will be about 5-10% lost, but among them will be impurities, soluble in acetone. also pretty pure salt as the result worth sacrifices.
i will test with NaCl if i hve time. I need to add some other compound abot 20% similar with that from liquid leftovers, what can be used?

 

[Mr Good Cat]

or another way is to get the leftovers completely dry, then add water in volume equal to containing in 37% hcl. then add acetone accordingly. water dissolves most of impurities, another part of impurities will be dissolved in acetone, then pretty pure salt percipitates.
i also noticed, solubility of hydrochloride with impurities is less then pure one.

 

[Mr Good Cat]

Just got the result from a lab. Sample was after triple re-crystallization. Base extraction was not done for this batch.
Crystallization was done in 3 steps

1 - Crystallization in water

2 - Re-crystallization in IPA. Here is the result.


3 - Re-crystallization in water. Here is the result. Lab test shown 87%.
Sample on the left is from the same batch, but double crystallization in water only (IPA skipped!!!)


Considering, IPA is a best solvent for this black compound, my estimation as 10-20% of this black compound in initial mixture is more or less reasonable and precise.

Unfortunately, my greediness didn't allow me to test another sample after base extraction. It would be interested to compare results.

 

[G.Patton]

So, do you have data bout its purity after IPA recrystallization or after water recrystallization only?

 

[Mr Good Cat]

this result 87% is after all these 3 steps done.
i mean sample on the photo after step 3 was sent to a lab. it is final product that was obtained after all these 3 steps done one by one: water, ipa, water again.

 

[G.Patton]

I found a good explanation of MDMA recrystallization with IPA. Does your procedure similar? I mean exactly moment with "to cool it as slowly/gradually as possible to ensure slow crystal formation".

Put your dry MDMA HCl in a beaker and set it aside for later. Now in a separate beaker boil 10-15ml 99% IPA per 1g MDMA HCl in a beaker in a shallow oil bath with a stirbar on medium, it is best to use an excess of more IPA than you’ll really need in the beaker. Gently lay a sheet of aluminum foil over the top of the beaker, don’t wrap the aluminum foil over the beaker so it’s air-tight because that might create excess pressure within the beaker, the goal is to just lay a small sheet over the open beaker to keep moisture in the air from getting into the IPA since anhydrous IPA is hygroscopic. Once the IPA is hot/boiling then remove the sheet of aluminum foil and reduce the volume of IPA a little bit to azeotropically remove the ~1% H2O present in the IPA, then remove it from the hot oil bath and slowly pour it or use a pipette to add boiling IPA to the other beaker containing the MDMA HCl. This must be done quickly so that the dry IPA doesn’t absorb H2O from the moisture in the air. Be sure to add just enough IPA to dissolve the MDMA HCl, you want to use the absolute minimal amount of boiling IPA. Swirl the beaker around after adding IPA to the MDMA HCl, you may carefully put the MDMA/IPA beaker on the hotplate to warm it back up as the IPA will cool off when you remove it from the heat to add it to the MDMA HCl. If you decide to put the MDMA/IPA beaker on the hotplate then continue swirling it across the surface of the hotplate and be careful not to hold it there too long, just a few moments to warm it back up again. You want all (or like 99 percent) of the MDMA HCl to be dissolved then cover the beaker with aluminum foil to seal it, pinch the edges of the aluminum foil around the beaker to make it airtight. Now let the beaker with the IPA/MDMA slowly cool to room temperature on its own. Once it has reached room temperature or is cool enough to where it’s only warm to the touch, then add 4x volume of freezer-chilled anhydrous acetone in relation to the amount of IPA you used. This is to help lower solubility of the MDMA HCl in the IPA. You wait until the IPA cools off before adding the acetone otherwise the acetone would flash boil. Now carefully move it to the refrigerator, once it has reached the temperature of the refrigerator then move it to the freezer. The goal here is to cool it as slowly/gradually as possible to ensure slow crystal formation, you want to be as careful as possible and not agitate the solution as that will disturb crystal formation. After approximately 30 minutes in the freezer you’ll start to see precipitation, however you’ll want to keep it in the freezer for longer. Once it has been in the freezer for anywhere from 8-24 hours then carefully vacuum filter off the crystals over a #103 filter by barely holding the vacuum tube to the barb on the filter flask to apply a light vacuum. Wash the crystals with a small amount of freezer chilled dry acetone if necessary. Now spread the crystals out over a drying dish and let the crystals air-dry (or use a very low heat source like a heat lamp).​

 

[Mr Good Cat]

My process is even more simple, but precise:
- i heat IPA up to 55-60C
- i prepare PP erlenmeyer flask containing mdma hcl
- i add hot ipa in the flask by weight 2.7 gr ipa : 1.0 gr of mdma hcl
- i close erlenmeyer flask and keep it on water bath gradually decreasing temperature, about 2C per 1 hour that is a real nightmare if done manually

 

[G.Patton]

Sounds like you have to get almost transparent MDMA*HCl crystals.

 

[Mr Good Cat]

exactly. you are right, crystals look pretty pure and transparent. but lab test say 87% only.

so it is either about a high percentage of black compound (about 20%) that was partially removed with ipa, or it is about testing system.
me personally believe, it is black compound.

 

[hacke8]

Hello, gentlemen, I have encountered this situation when preparing methamphetamine from pseudoephedrine. I guess they are caused by excessive acidification and water. This black complex feels like iron hydroxide colloid, which is very stubborn, but they are soluble in ethanol/methanol and insoluble in other organic solvents. My last solution is to dissolve all the substances in anhydrous ethanol, put them in a semi-permeable membrane, and then put them in a beaker containing distilled water. Under the stirring, let methamphetamine hydrochloride enter the water through the semi-permeable membrane, while the black complex remains in the semi-permeable membrane. The final product is very clean and creamy white. But it is very time-consuming.

 

[Mr Good Cat]

It is interesting. May you describe the process in details please?

 

[hacke8]

The operation method is very simple. The semi-permeable membrane is a bag with a solution inside. After sealing, it needs to be stirred to make the collector pass through (or other liquid that can dissolve the collection). This is very time-consuming.

 

[Mr Good Cat]

If I understand correctly, you operate with hydrochloride salt of pretty high purity 85+ purifying it to 95+? How much time does it take to process a kg of stuff hcl? Any comments and specification of used membrane?

 

[Mr Good Cat]

If I understand correctly, this membrain is unpermeable by certain compounds, some by salts, some by charged ones. It could be me effective than resins, depends how much time it takes.
Perhaps, some automation of the process could be done.

Btw, you mentioned iron salt. But how did this iron came to the product?