03-17-02 09:22
No 283792
I've become disenchanted with IPA for absorbing HCl gas and am open to alternatives.
Don't get me wrong, IPA absorbs HCl like a sponge (over 38% has been taken up, at times) and has a long shelf life before any color change (color change being the visual clue that HCl is doing something funky to the solvent) or conversion to IP chloride.
The problem lies in crystallization of amine freebase oil. IPA seems to dissolve too much of the hydrochloride, even at freezer temperature, which then must be recovered by secundary step of boiling off all the solvents, convert to freebase and distill again for a second round of crystallization. There is mechanical and chemical loss with each additional manipulation. Loss needs to be avoided.
Gassing acetone with HCl works great in terms of getting maximum recovery of hydrochloride crystals the first time around, but acetone will quickly react with HCl(g), so shelf life is limited to a few hours, not weeks, like IPA. Acetone will work for small quantities. But not for larger amounts of gas.
So what do you use? Toluene? Xylene? Once I get enough good suggestions, maybe a round of lab experimentation will determine a winner, and all of us will benefit. We each have our favorite, but who knows? maybe one is superior.
The criteria are:
1. Ability to soak up HCl(g) and not react, thereby being useful for gassing one day and crystallizing some other day.
2. Low solubility of our favorite hydrochloride crystals in said solvent.
3. Non-watched. Ethyl ether is fairly watched, but all others seem to be OK.
4. Quick evaporation and no residual smell (unlike toluene) that might adhere to the product.
Suggestions?
Regards
Argox
P.S. Please no posts about using HCl(aq) and then boiling dry, or anything about HCl(aq). Thanks.
In the port of Amsterdam, there's a sailor who sings
Of the dreams that he brings...
(Distinctive Doe)
03-18-02 00:32
No 284020
"The problem lies in crystallization of amine freebase oil. IPA seems to dissolve too much of the hydrochloride, even at freezer temperature, which then must be recovered by secundary step of boiling off all the solvents, convert to freebase and distill again for a second round of crystallization. There is mechanical and chemical loss with each additional manipulation. Loss needs to be avoided"
What solvent are you crystallizeing the freebase from?
Or is it just plain freebase?
My suggestion.
Why use so many steps to recover?
It can bee done quickly and easily by useing a protocol similar to what you would use to recrystallize from IPA.
Filter off the crystalls you get initially from addition of gassed IPA.
Then evap. MOST of the IPA and crash the rest out with acetone. No real extra steps except a final recovery.
Those who give up essential liberties for temporary safety deserve neither liberty nor safety
(Her Majesty, Stoni's Kitty)
03-18-02 00:32
No 284021
Solvent combinations are the way to go.
Drip HCl-IPA into solvated basic product in toluene (dry) until crystal precipitation occurs and the pH is either neutral or acidic. Filter and dry. Weigh product. Add methanol equal to half the weight of the dried crystalline product and heat in water bath and swirl until product is dissolved completely. If necessary, add more methanol, one mL at a time until complete dissolution occurs. Then add about ten times the weight of acetone (dry) and put in the freezer. In about two hours, crystallization occurs. White and in chunks. If too much methanol was used accidentally, follow same proceedure but give a day for crystallization.
(Hive Bee)
03-18-02 00:59
No 284034
Hi Kitty!
So you say mix freebase with toluene, then drip IPA-HCl to crystallize. In other words, you say IPA is best solvent to take up HCl. And you use a toluene system for 1st round crystallizaton. Do you have recovery data? How much crystal is recovered in 1st crystallization vs. how much remains in solvent and must be recovered in 2nd and 3rd?
The MeOH-acetone you mention is just a re-crystallization to increase purity. OK for small scale personal use product, not necessary otherwise.
See, the problem is 1st round recovery vs. 2nd and 3rd round recovery. Purity is not the issue. Yield is. The more freebase is converted to crystal and recovered from the 1st round of solvents, the better overall yield, since freebase is lost or polymerized in subsequent manipulations.
My question should have been more clear. Acetone is the best overall solvent for crystallization, since amine hydrochloride is sparingly soluble and acetone is highly volitile and leave no residual odor. MeOH is lousy solvent for crystallization, since amine hydrochloride is very soluble in it. In between are a range of solvents from which to choose.
The question is, since acetone is lousy for taking up HCl(g), which other solvent is good for taking up HCl(g) and also has negligible soluting effect on amine hydrochloride?
Bear in mind that yield and ease of manipulation are primary concerns, not so much purity. We're talking Burger King here, not the Four Seasons.
Edit--Kitty, from your description of MeOH and crystal chunks, it just dawned on me that you are probably talking in terms of meth. I'm only interested in mdma.
In the port of Amsterdam, there's a sailor who sings
Of the dreams that he brings...
(Stranger)
03-18-02 03:43
No 284120
Swim actually dreamt of your method Argox. This is how the dream went:
In the first dream swim dripped in the the hcl/ipa into a toluene/freebase solution with stirring. After the stirring was stopped the crystals quickly settled at the bottom of the beaker unlike gassing directly which produces a thick milk shake. The crystals were filtered and a second "gassing" produced minimal crystals.
The crystals were weighed and the results were exactly to the gram the same as in previous direct gassings. The ipa/hcl was stored in the freezer and swim was a very happy bee indeed as he thought he would'nt have to gas for a very long time.
About a week later swim went for another round and his yeild went down about 30%. He thought that it was because of something he tried differently in his Al/Hg amination. He left it in the freezer over night but still no more crystals.
The next time he aminated his usual way and the yeild was even worse than the second time. Swim's dumb ass tossed away what he now knows was freebase still in toluene for a second time. Who would of thought it was the ipa/hcl which workes so well a week earlier? Don't answer that. Swim gassed again from the same tone and everything worked as usual. Something happens to the ipa really fast which makes it solvate mdma (at least in toluene).
I know this does'nt answer your question but swim wanted to share his dream.
Triton
(Distinctive Doe)
03-18-02 07:29
No 284193
"Something happens to the ipa really fast which makes it solvate mdma"
I'll bet that absorbs water faster than anything. If the air is even slightly moist, its probably slurping up the H2O as fast as it can.
Those who give up essential liberties for temporary safety deserve neither liberty nor safety
(Hive Addict)
03-18-02 09:49
No 284233
Gassed Et2O works like a charm. Gassing is easy, and you can store it for months without problems. The only `problem' is that sometimes you might need to add some more IPA (or ether) because the whole mess becomes to clunky,
so you can't see if you've xtalized all your freebase.
(Daddy)
03-18-02 23:54
No 284463
I do not fully understand the reason for storing solvents which contain a certain percentage of HCl gas.
I would never do it, because of the unpredictable chemical reactions over time with the solvent.
Toluene seems like a good alternative, and perhaps DCM, to answer your initial question, but for just a few hours, however I've stored them at times for much longer periods. Did not have the time back then to compare yields from fresh solvents to yields when using in forced situations a stored solvent/HCl solution.
Fresh Acetone, Toluene and DCM (all low hygroscopic), mixed with fresh freebase MDMA, at a ratio of minimal 8:1, and then gassed gave always highests yields, as the first massive crystal collection.
Gas the collected filtered-out solvent again and filter off a second small portion of crystals.
Do not forget to gas the combined subsequent acetone washes of all your crystals again, to collect a third very small portion of crystals.
Freebase will always adhere to and inside the crystal structures, thus the third wash is more a soaking of your crystals for a night, then filtering.
To speed up things, do not filter but use a centrifuge to precipitate the crystals in 5 minutes.
It also decreases mechanical losses. Just decant the solvent or pump it off.
DCM is a special to me, in most cases it's better to gas inside your 22 liters, and evaporate all the DCM at reduced pressure. Then add acetone to the dry, brownish crystal mass, and decant the sludge, filter, while pouring acetone over the crystal mass in your buchners, resulting in snow white crystals.
This way you use way less acetone, and acetone is exactly the smell you don't wanna bother your neighbours with. DCM will not smell this way, because it is condensed in your distillation setup, and collected in a 22 liter receiving flask.
Chemical engineers will use 150 liter SS tanks to do this.
McGuivers will do all the processes in a 1500 liter milktank, so included the gassing and washings, it's that warm fuzzy feeling you get when shuffling 5 kilo crystals per swing from the bottom of your milktank, which you'll never forget. LT/
WISDOMwillWIN
(Chief Bee)
03-19-02 06:52
No 284679
Labtop: Do you need any assistants to do that hard work for you?
Wading through MDMA Hydrochloride is something I have never done before...
(Hive Bee)
03-19-02 11:20
No 284749
Jeez, L/T, my pecker just shriveled up. You win the dick sizing contest. Congratulations.
Not like you, though, to mention the nuclear arsenal when a fire-cracker would do. Saint Patty's was a couple of days ago. Still at it?
The centrifuge is a nice touch. Very impressive.
Edit: I'm just kidding about St. Patty's, everybody knows you gave up single malts for lent. Cheers!
In the port of Amsterdam, there's a sailor who sings
Of the dreams that he brings...
(Daddy)
03-20-02 00:53
No 285048
I'm retired, everybody forgot? I recall my past adventures. Way past btw.
Btw, when buchnering that acetone sludge, have a valve between your 100 liter SS vacuum flask and your aspirator station, and close the valve when you have full vacuum in the flask.
That way, by refilling a few times your 50 cm SS buchner, when the acetone level is 1 cm, you maintain vacuum, but NO acetone smell at all will escape your setup.
Just use new vacuum when you suck all last added acetone out, when your crystals are snowwhite.
Sounds like a Disney cartoon, feels the same btw when busy with this.
Always use icecold acetone, this will have no smell to mention.
And blow air in your drain for 30 minutes after that last acetone vacuming with the aspirator, that way the drain will explode at the neighbours instead under your hideout, when you throw your cigarette stump in the drain pipe. LT/
WISDOMwillWIN
(Hive Bee)
03-20-02 01:11
No 285057
Oh man, that's the best chuckle I've had in a week!
Thanks, L/T!
In the port of Amsterdam, there's a sailor who sings
Of the dreams that he brings...
(Hive Bee)
03-20-02 10:52
No 285288
Toluene seems like a good alternative, and perhaps DCM, to answer your initial question,
I've calmed down, so will proceed delicately. Uh, LaBTop, buddy, toluene does not absorb HCl gas. I can tell you this for a fact. After first couple of grams dissolve, the toluene turns opaque and the rest of the gas just passes through it. Cold toluene, btw. Man, somebody was cursing up a storm a little while ago, as he quickly switched out toluene for another solvent.
So I guess you never actually tried gassing toluene before you posted that it would work.
SWIA ended up using acetone to absorb HCl(g). It works great, if dry, and if you use it right away. No good for storage or next day, though.
I may research this and report on actual results. Test a number of solvents. Try and separate fact from fiction, so to speak.
Regards
Argox
In the port of Amsterdam, there's a sailor who sings
Of the dreams that he brings...
(Chief Bee)
03-20-02 22:09
No 285491
ACTUAL results - I like that attitude Argox, keep up the good work!
(Hive Bee)
03-21-02 02:49
No 285574
Like my shot-gun buddy from Bolivia always said, Practicando, practicando, uno llega a ser madre.
Who knows, when this is all worked out, maybe a new sticky thread, based not on what worked once for one guy, but what has been researched to be best.
In the port of Amsterdam, there's a sailor who sings
Of the dreams that he brings...