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Ammonia wash AND recrystallization?

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AI

Rising Star
Hello,

Sorry if this has been asked previously, I couldn't find anything with the search.

Using Noman's technique, should one do an ammonia wash as well as recrystallization, or will recrystallization simply suffice?

I ask because I read this: "You will end up with DMT crystals of varying purity atop a pellet of slag which still contains quite a bit of DMT but also lye if you skipped the ammonia wash."

If one were to skip the ammonia wash, would these dmt crystals that were recrystallized in solvent (heptane, perhaps, hypothetically?) possibly have lye on them/result in an unpure product, or is it possible to completely separate the sludge from the pure crystalline product?

Also, would one re-add this sludge to further recrystallizations, or would one want to re-add the sludge to the naptha solution prior to precipitation in the freezer?

I apologize if I asked too many questions :)
 
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the simplest way to clean your compound of polar impurities like lye is after collecting all your non polar fractions before evaporating the solvent or freeze precipitating is rinse with some basic water solution. some people complain about ammonia wash but i see no real reason why. you can also use sodium bicarbonate and sodium carbonate. just rinse your naptha or whatever solvent you are using a couple times quickly and all the lye (if there was any) will be gone. other non polar impurities can be removed by recrystallization. both are easy things to do and i recommend both if one is seeking more purity. recrystallizing will not effectively get rid of lye as well as basic washing. and washing with basic water solution will not get rid of non polar impurties as well as recrystallizing.

and no need to apologize if you want more information please ask.
 
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Damn that ammonia wash!
I wish I'd never put it in that tek.
With an eye towards replacing it with a polar wash of the solvent, my friend did some tests washing his solvent with sodium bicarbonate, ammonia, and calcium hydroxide solutions.
He got 160mg from the calcium hydroxide, 100mg from the ammonia, and a little puddle of yellow oil from the sodium bicarbonate.
Unfortunately, he's an idiot and didn't evap an equal quantity of unwashed solvent.
Asking around, a friend on another forum told him that the alks will tend to migrate into the polar wash if the pH is not significantly higher than the pka of DMT (8.68).

"For an alkaloid, logD would be highest at pH 7 and lowest at pH 12, so more of the alkaloid will partition into the aqueous phase in the bicarbonate, less in the ammonia, and the least in the Ca(OH)2. I believe that is what you have observed. The important thing is to have the pH of the wash higher than the pKa of the amine, or it will preferentially go into the aqueous layer. Tertiary amines have pKa's of about 10-11. However, if one uses hexane or heptane for the MHRB extraction, it would not seem necessary to perform the base wash, since they are selective for extraction of tertiary amines."
 
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noman you are totally right that the pH should be much higher then the pka. this can be achieved easily with sodium carbonate note not bicarbonate. i am a bit curious though if the pH were the same why would it matter what base was in it?

the only reason to really do an alkaline wash in an alkaloid extract like this is if one didn't separate ones phases well in the interest of saving time and some of the basic water got stuck in the organic layer in the form of emulsions, or bubbles, or just because it dripped too much etc. the trace amounts of lye that might get into a solvent like hexane from the phases reaching some kind of equillibrium are trivial and most likely removed during a recrystallization. trying dissolving lye in hexane you'll see what i mean. its the easiest thing in the world to do to rinse your non polar solvent with a pH 11 or 12 solution of sodium carbonate. if someone were trying to accomplish a quick non polar extraction and didnt want to sit around forever waiting for emulsions to completely go away or worry too much about sucking up some of the basic water or whatever its a harmless way if done properly and quickly to clean ones organic phase up. i should clarify that when i speak of washes i always mean rinsing the organic solvent and not the product itself.

sorry for the rant but this should be cleared up because the polar ammonia wash thing does seem to cause a lot of confusion.
 
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burnt said:
the simplest way to clean your compound of polar impurities like lye is after collecting all your non polar fractions before evaporating the solvent or freeze precipitating is rinse with some basic water solution. some people complain about ammonia wash but i see no real reason why. you can also use sodium bicarbonate and sodium carbonate. just rinse your naptha or whatever solvent you are using a couple times quickly and all the lye (if there was any) will be gone. other non polar impurities can be removed by recrystallization. both are easy things to do and i recommend both if one is seeking more purity. recrystallizing will not effectively get rid of lye as well as basic washing. and washing with basic water solution will not get rid of non polar impurties as well as recrystallizing.

and no need to apologize if you want more information please ask.
Click to expand...

Aha, thanks! I hadn't read about this sodium carbonate wash until coming here and looking around.

Noman said:
Damn that ammonia wash!
I wish I'd never put it in that tek.
Click to expand...

Ha, well, whatever the case you ended up with a very easy-to-follow tek that makes a lot of sense... so thank you :)

Noman said:
With an eye towards replacing it with a polar wash of the solvent, my friend did some tests washing his solvent with sodium bicarbonate, ammonia, and calcium hydroxide solutions.
He got 160mg from the calcium hydroxide, 100mg from the ammonia, and a little puddle of yellow oil from the sodium bicarbonate.
Unfortunately, he's an idiot and didn't evap an equal quantity of unwashed solvent.
Asking around, a friend on another forum told him that the alks will tend to migrate into the polar wash if the pH is not significantly higher than the pka of DMT (8.68).

"For an alkaloid, logD would be highest at pH 7 and lowest at pH 12, so more of the alkaloid will partition into the aqueous phase in the bicarbonate, less in the ammonia, and the least in the Ca(OH)2. I believe that is what you have observed. The important thing is to have the pH of the wash higher than the pKa of the amine, or it will preferentially go into the aqueous layer. Tertiary amines have pKa's of about 10-11. However, if one uses hexane or heptane for the MHRB extraction, it would not seem necessary to perform the base wash, since they are selective for extraction of tertiary amines."
Click to expand...

Interesting.
 
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sorry to keep revisiting this subject matter. my friend Salah uses Noman's tek, and was doing ammonia washes for awhile, but now that ammonia washes aren't in vogue around here, he was wondering about baking soda washes. The problem with that is, he cannot get the pH of baking soda wash high enough to offset this:


"For an alkaloid, logD would be highest at pH 7 and lowest at pH 12, so more of the alkaloid will partition into the aqueous phase in the bicarbonate, less in the ammonia, and the least in the Ca(OH)2."

However, Sal read in this thread : Do I need an ammonia wash? - FAQ - All your basic questions and answers - Welcome to the DMT-Nexus that baking soda is fine to use as a wash. Which is true?

Sal is of the mind to not do a wash at all, and just recrystalize one or two times. However burnt reports that : "recrystallizing will not effectively get rid of lye as well as basic washing"

Ok so Sal doesnt have access to sodium carbonate, only baking soda and ammonia, is there some easy way out for him?

thanks for help in advance
 
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baking soda works according to those who've used it. im a bit confused how can you not get the pH high enough? just add enough to pH is around 10 or 11. 7.8 grams of the stuff dissolves in 100mL water so solubility shouldnt be a problem.

"For an alkaloid, logD would be highest at pH 7 and lowest at pH 12, so more of the alkaloid will partition into the aqueous phase in the bicarbonate, less in the ammonia, and the least in the Ca(OH)2."

logD refers to the partition coeffecient of a substance between water and octanol. i dont understand how more of the alkaloid will partition into aqueous layer if the pH is high that doesn't make sense to me.
 
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burnt,

thanks!
sal will try to dissolve more baking soda into the water, he didnt think that much would dissolve. plus from his readings on the forum there seemed to be some contention about bicarbonate vs. carbinate washes...he will try now and report results on this thread
 
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salah dissolved as much baking soda as 100ml of water will hold, but his ph paper still reports a ph of about 8 or 9. he then added even more baking soda, fltered out the excess and then added this solution to his first pull of naptha (about 200 ml) he stirred and mixed these two for a minute or 2 then siphoned out the naptha and placed it in the freezer. i will report his results in a few hours...
 
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the baking soda(bicarbonate) wash worked for me. it removed much of the yellow oil and i was left with very white crystals. i can't tell you that it removed excess lye. but it looks so much cleaner!
1tps spoon baking soda with 150 ml water.
a ratio of 1:10 1 part soda wash:10 parts naphtha+dmt was mixed and separated.

and it resulted in only a fraction of weight loss.(this ~2% of weight loss is highly suspected to be oils)
 
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cool!

this all sounds positive. sal's first pull is in freezer and fogging up nicely, will let you know how it looks tomorrow or late tonight. he will eventually check loews or home depot for sodium carbonate, so he can avoid low ph wash in the future...
 
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yea the higher the pH like 11 or 12 the better for losing less yield. well its basically the higher the pH the less likely that any of your spice will be ionized and dissolve in the water phase. if its lower pH then its more likely that a small amount may be ionized form and go into water phase. thats the theory side of it anyway.

the baking soda(bicarbonate) wash worked for me. it removed much of the yellow oil and i was left with very white crystals. i can't tell you that it removed excess lye. but it looks so much cleaner!
Click to expand...

it will for sure remove the lye. lye is soooooooooo soluble in water it has no desire to be in organic solvent.
 
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Ok here's the update:

Yesterday, while waiting for his first 200ml naptha pull washed in sodium bicarbonate to freeze precip, Sal's curiosity go the best of him and so he travelled around until he finally found sodium carbonate in the form of Arm and Hammer Super Washing Soda. He then took approx 1 gram of unwashed spice and redissolved that in 200 ml naptha, and washed that with sodium carbonate. He then had two jars in the freezer, one washed with bicarbonate, the other washed with carbonate.

One thing worth mentioning is that Sal was having trouble getting the PH higher than 8 or 9 with the bicarbonate wash, and that worried him. With the carbonate, a PH of 11 was easily achieved.

This morning, the difference is clear. The spice washed in bicarbonate is clearly more yellow than the spice washed in carbonate. He understands however that the bicarbonate batch was pulled straight out of the mimosa jar, and that the carbonate batch was unwashed spice RE-disolved into naptha, which can help clean it on its own (indeed some bits and oils did not dissolve and settled at the bottom and were removed)

Still, overall, given the amount of difference, Sal would strongly recommend carbonate over bicarbonate for washes.

Thanks for the helpful suggestions and encouragement as always
 
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