07-16-02 21:36
No 333489
I UTFSE and was wondering since there is a lot of interest in averting distillation via purifying with sodium bisulfite complex formation procedure.
One of the hindering factors I deduced that makes this impracticable I'm told is the prescence of alkenes (like isosafrole) which interfere with crystallization of the complex.
So SWIM proposes that the procedure be done with a two phase system.
For example: the extract after washing could be mechanically stirred over a saturated solution of sodium bisulfite.
It would seem that the organic phase would chemisorb most of the alkenes which are said to interfere with the complex formation.
Does anyone who has extensive personal expirience with this purification method, have any ideas to add or compliment this proposed modification?
Ancillarilly, a little bird tells me that alcohols are the best means of washing this complex to remove impurities trapped in the matrix.
Can anyone verify this as a service to us no glass havin, broke ass bees?
(Stoni's sexual toy)
07-17-02 00:56
No 333540
Yes, that works pretty well. Shake your ketone or aldehyde containing extraction solvent with bisulfite solution, filter the precipitate and wash with ethanol and ether to remove adhering impurities and you get pretty pure, dry bisulfite adduct. The ether wash isn't really necessary in most cases.
I'm not fat just horizontally disproportionate.
(Newbee)
07-17-02 02:06
No 333550
Very Nice MaDMAx
Clouds come and go and never stay still........
(Stoni's sexual toy)
07-17-02 04:19
No 333563
60ml Bisulfite sounds like a little too much.
Now add some NP solvent to the impure ketone and try again. I bet it will work better. At least it did for me.
I'm not fat just horizontally disproportionate.
(Hive Bee)
07-17-02 10:27
No 333659
I've heard a lot of people say that aminations don't work with bisulfite purified ketones.
But I think that the procedure was'nt done properly.
I got to go to the slam tommorow
but I like the way this post turned out.It will give me some food for thought.
(Hive Bee)
07-17-02 14:27
No 333787
see what happens when you take that yellow sloppy bisulfite adduct and rinse with a little alcohol.
Or, before you do that, add something nonpolar to the flask with the impure bisulfite adduct and see what happens with a little stirring.
(Synaptic Self-Mutilator)
07-17-02 17:06
No 333852
Osmium, in trying to purify asarone ketone, I found that:
1) it was destroyed by distilling at atmospheric pressure (unlike mdp2p, pmp2p)
2) using the oxime formation as a purification step gives nothing other than a sludge (that aminated!)
3) bisulfite purification doesn't work, as it gives the typical impure chicken fat result that MaDMAx is showing off in the pictures above
Can you please clarify what you mean by add a bit of NP and shake? Are you saying that beautiful bisulfite crystals of tmp2p will form if I add some NP (what would you recommend, DCM, toluene?), aqueous bisulfite, and stir? I notice in other posts you recommend not to use alcohol, did you use it when using a NP?
Thanks.
PS. MaDMAx, I was going to take pictures exactly like yours! Really! I was! I'm just lazy. =) I was going to do it in 3 or 4 test tubes though...
(Hive Bee)
07-17-02 17:47
No 333867
Has anyone checked to see if the NaI complex works any better?
(Hive Bee)
07-19-02 21:03
No 334920
ALA osmium via P.M. he get's a little more specific.In reply to:
----------------------------------------
Are you saying positively without a doubt that the two-phase bisulfite ketone complex procedure works to give nice white fluffy bisulfite addition products?
Yes. I did it myself. Ketone dissolved in several volumes of ether, shaken with saturated bisulfite solution. The whole flask was full of solid precipitate, filtered, washed with bisulfite, EtOH, then ether. Result was dry, slightly yellow bisulfite complex. It works.
So there you have it folks.
This needs to be expounded I think with a few success and failure tales to verify it's legitimacy.
Coupled with some freezing techniqes thanks to Madmax and others this makes M.D.M.A. without glass a viable possibility (as opposed to the previous collective wisdom of this site), for all the economically disadvantaged or paranoid expirimenters.
(Stoni's sexual toy)
07-20-02 06:35
No 335051
Forgot to mention, bisulfite solution was only water, no alcohol added.
I'm not fat just horizontally disproportionate.
(Synaptic Self-Mutilator)
07-20-02 06:52
No 335055
SPISSHAK, I don't see why you would ask the question in a PM before you'd ask a public message... if you've got a question, more than likely ten other bees have the same question. I had the same question, asked it via the message right above, then directed Os to the post after seeing that I might not get an answer from Os.
Thank you for sharing the PM, but... do you think we could all share this information publically in the future? It would benefit all of us! I hate to think of all of the other useful information that's slipped through, via PMs, into the ether of the internet.
I think there's been another post from the mods on exactly this subject.
(Hive Bee)
07-20-02 16:11
No 335243
Don't try and purify your crude ketone by forming the bisulphite adduct and cleaning it. It doens't work very well at all and it's messy too, believe me it's a bloody waste of time. Just get yourself a vacuum destillation set up B4 even trying these synths. I tried purifying crude ketone with metabisulphite and it was chicken fat central that didn't seem to clean up whatsoever.
I would just use the rest of your sodium bisulphite in testing for presence of ketone, that's what it's best for.
OB1
(Hive Bee)
07-20-02 16:40
No 335259
But the point is there can be improvements like the one above that can make the whole thing a lot more convenient.
I take it that you just added crude ketone to a saturated solution of sodium bisulfite without any of these modifications, like dissolving in ether or similar nonpolar solvent, to get the notorious "chicken fat".
Am I correct?
(Old P2P Cook)
07-20-02 17:56
No 335296
But the point is there can be improvements like the one above that can make the whole thing a lot more convenient.
While it is admirable to want to develop procedures that enable the synthesis of MDMA without the need for a vacuum pump and with the minimum of glassware, the tradeoff will be in poor yields of product. Purification using bisulfite just gives poor recovery of ketone. I experimented with preparing the MDP2P-bisulfite and then regenerating the MDP2P and got poor yields even when I started with pure, distilled MDP2P.
(Hive Bee)
07-20-02 20:29
No 335353
So where do you think the losses went?
In an incomplete bisulfite adduct precipitation, the washes, etc.?
I guess the question is, obviously the losses were mechanical, so what procedure did you notice gave poor returns?
(Old P2P Cook)
07-20-02 20:57
No 335359
It has been a long time but I believe that the losses were due to incomplete precipitation of the adduct. I was using the bisulfite prepared according to Vogel with water/methanol. Osmium and others here have used bisulfite solution without any methanol; perhaps that would work better.
(Title on BackOrder)
07-21-02 02:16
No 335426
Forming the bisulfite wouldn't serve as an alternative to vacuum distillation of ketone, but it could greatly aid in reducing the amount of tar left over in the bottom of the distilling flask from after a peracid/acid hydrolysis reaction. If you could form the bisulfite complex with quantitative yeilds, followed by cleaning, reclaiming the ketone, and distilling, you would eliminate a large quantity of the tar that is left over even after your caustic ketone washes. I imagine everyone here hates having to clean glassware, as it means extra time not spent performing reactions.
All paths are the same: they lead nowhere
(Stoni's sexual toy)
07-21-02 15:11
No 335552
My ketone distilling flask cleans itself, simply by standing in a corner of the fume hood with some acetone or alcohol inside for a day or two.
I'm not fat just horizontally disproportionate.
(Title on BackOrder)
07-21-02 15:35
No 335561
Most bees don't like to have glass out in the open for a day or more, and we also don't like to have acetone evaporating out in the open when we're not there.
All paths are the same: they lead nowhere
(Synaptic Self-Mutilator)
07-21-02 16:31
No 335576
Acetone has always cleaned out the flask in a jiffy for me. I try to never distill the oil so far that it burns... I always remove the heat from the flask when the last of the ketone is coming over...
(Title on BackOrder)
07-21-02 17:19
No 335586
If you are distilling ketone and have it up to a vigorous boil around ~102-110C, and decide to break down your glass and collect out a fraction quickly, your distillate will turn into tar upon disconnection of the vacuum source and quick repressurization. I did this once, and ever since then I have made sure to remove the distilling flask from the oil bath and allowing to cool before collecting fractions. You can't add acetone to a flask that is currently 120C, and by the time it cools down to 50C you have a hardened lump at the bottom.
All paths are the same: they lead nowhere
(Old P2P Cook)
07-21-02 17:33
No 335587
BTW, the yield of bisulfite complex from the 1 gram of clean ketone was 1.6 grams of dry, bright white powder.
So, you are claiming a quantitative yield:
(178+104)/178 = 1.6
(Synaptic Self-Mutilator)
07-21-02 18:12
No 335594
Awesome! That's a 95%+ yield if your crystals are absolutely dry (1.6g / 1.67g). Now, MaDMAx, just tell me another solvent to use other than ether to get the bisulfite adduct to form from impure ketone, and I'll love you forever!
I suppose I should be doing those experiments myself... but I'm being a lazy bee.
(Hive Bee)
07-21-02 20:02
No 335625
for those of us less fortunate than most, this procedure verifiably can be used(if done correctly) to circumvent fractional distillation of ketone.
I UTFSE and have read of one account where MDP2P was purified via bisulfite procedure and subsequently aminated after washing with alcohol and the result after a Nitro Al/Hg reduction was %60 yeild, the usual result of impure ketone (ie. peracid produced and washed with NaOH, water) was anywhere from
%10-to nothing.
So after careful research of case examples, this is feasible if need be for those of us in a pinch.
Although classical purification methods are less tedious.
I'm not trying to deliberatly take shortcuts but it's nice to calculate all of the possibilties, rather than assume to know everything needed to know.
(Hive Addict)
07-21-02 22:11
No 335655
I would think using excess water and a hard shaking would allow the adduct to seperate from the alkene. I would also add that the adducts from impure usually has a mixture smell of iso and glycol. however Swim couldn't get crystals to form then either, But not much effort was applied.
VL_
(Synaptic Self-Mutilator)
07-26-02 11:39
No 337430
Ok. I took 0.2ml pmp2p, 1ml DCM and stirred with 5ml bisulfite. It stirred for a day with no adduct forming. I boiled off the DCM and the beautiful white crystals formed. I then added DCM to the test tube. The bisulfite adduct was not soluble in the DCM.
Any other ideas? I don't have any substancial amounts of ether around.
(Stoni's sexual toy)
07-27-02 13:56
No 337813
Stirring is usually not good enough. You have to shake the shit out of it O2 wacker style.
Try toluene, or xylene. And use less bisulfite solution.
I'm not fat just horizontally disproportionate.