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Pumukli
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Seems to be a good idea.
Also, the note about not being pure product but a mixture of MeNH2 and others (I tend to think mostly ammonia).
In the benzene from benzoic acid (or what) thread they used fine metal mesh to improve heat conduction to avoid hotspots and achieve thorough even
heating. Maybe it wouldn't hurt in this case either.
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DIBALL
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I tried to determine the melting point and some of it decomposed like Ammonium Chloride, so like Pumukli mentioned, it is probably a mix of
Methylamine and Ammonia.
Looks to me that too much heat and NaOH is too "aggressive" and converts a lot to Ammonium Chloride.
I would like to try the "sand method". What was your sand/glycine ratio?
Also I might go back to the "peppermint" idea. Maybe it´s more selective for Methylamine.
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zed
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Well, what reaction path is being followed in this sand-decarboxylation is difficult to project. Perhaps SiO2 somehow catalyses the reaction.
Sometime in the past, I read a paper wherein water separation was used, along with a ketone, to form the imine in bulk, followed by higher
temperature decarboxylation of the imino-acid.
Had the paper somewhere. Darned if I can find it.
Copper Chromite might be a good catalyst. Seems to do the trick fer decarboxylaing nicotinic acid, to pyridine.
[Edited on 29-3-2018 by zed]
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Chemi Pharma
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Seems that we're all concluding that glycine decarboxylation with a strong base and elevated temperatures like carboxylic acid does it's impracticable
with aminoacids, to produce even a modest yield of methylamine, like I said.
If this was a viable method, off course someone already had found some paper, research or recipe about that somewhere. But it's not the case until
now.
Better follow the ketone-imine (schiff base) decarboxylation way, method that's well covered by many research studies and even here, at
sciencemadness. See this thread:
http://www.sciencemadness.org/talk/viewthread.php?tid=74727&...
[Edited on 29-3-2018 by Chemi Pharma]
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zed
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Time will tell. It should be noted, that the method you are currently espousing, was not widely known a generation or so... ago.
The idea of producing easy tryptamine or phenethylamine, was quite alien.
Over the last 40 to 50 years, practical approaches to decarboxylation of aminoacids evolved.
At the moment, known pathways are limited. Surely there are more to be discovered.
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DIBALL
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Quote: Originally posted by zed  |
Copper Chromite might be a good catalyst. Seems to do the trick fer decarboxylaing nicotinic acid, to pyridine.
[Edited on 29-3-2018 by zed] |
NileRed did once a video on decarboxylating nicotinic acid to pyridine with basic copper carbonate. I tried this too with Glycerine, but nothing
happened. Maybe the temperature was too low or heating it in dry form (and badly mixed) was a problem.
I´ll try the peppermint method next week. I can´t see why this shouldn´t work.
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zed
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I've seen those videos. Copper Carbonate works poorly. Copper Chromite works very well. Seems to me Doug's Lab has a nice procedure.
I mentioned this because Nicotinic Acid, seems structurally quite similar to the imino-acids we are attempting to decarboxylate.
Copper Chromite accomplishes this decarboxylation, at right about 100 C.. A much lower temperature than that employed in most procedures.
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DIBALL
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So, I have some updates and some things that I can´t figure out, so I hope you can help me.
A week ago I did the first decarboxylation:
I put 2g of glycine into 30mL of DMSO and 10 drops of the spearmint oil into a 100mL round bottom flask and connected it with a hose to a flask with
diluted HCl solution. The glycine didn´t dissolve properly though.
When I started heating I noticed a little bubbling occurring at around 120 degree, which I thought was maybe the peppermint oil boiling, but then I
saw, that it came from the undissolved glycine powder. Gas came over to the HCl solution. At the DMSO reflux temperature the bubbling got stronger and
stayed constant. Since I didn´t used a reflux I stopped when the DMSO reached the hose. It was interesting to see, that the bubbling continued, even
after I turn off the heat and it stopped, after all the undissolved glycine disappeared!
Then I boiled off the HCl solution, but in a moment, where I wasn´t watching, I burned it...
So I tried this again, but this time with less DSMO (20 mL) and 5g of glycine. Also I added a reflux condenser and switched to a phosphoric acid
solution.
This time I noticed, that even without heating already a bit of gas came over! But it was a bit slower now, which I think was due to a lower DSMO
amount. Then I realized that some crystals are forming in the condenser. I measured the temperature of the part of the condenser that wasn´t cooled
and it was not the temperature at which glycine is boiling.
After some time the condenser was cloaked and a mini "explosion" occurred, where the rubber stopper jumped out of the flask. It was smelling like
ammonia and reminded me of methylamine.
I stopped the reaction then and evaporated the H3PO4 solution and noticed, that it was reddish and stopped at about 5mL. Next I will see if cooling it
will get me some crystals.
But I have the feeling, that there was some side reaction with the DSMO? I´ve read that it can methylate methylamine in acidic conditions, but might
there be some reaction with the glycine? I mean the crystals in the condenser and the HCl and H3PO4 solution had a sulfuric and ammonia smell.
Should I use another solvent like turpentine?
But aside of that, it looks like the decarboxylation works really well!
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Pumukli
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In Scr0t's pirrolidine synthesis there is a lot of turpentine, a small ammount of spearmint oil and no DMSO - although the reaction time is 20 hours
at reflux temp. (around 160 C) and he had had solubility problems. He suggested using a small ammount of DMSO to help with the solubility though.
Link:
http://www.sciencemadness.org/talk/viewthread.php?tid=64791
So yes, turpentine may help.
On the other hand I can't really help with the side reaction, the reddish color of phosphoric acid soln. or the mini explosion. Btw. wasn't this later
one caused by a simple mechanical blockade of the vapour path in the condenser? Was not this blockade caused by (methyl)ammonium-carbonate build-up?
Edit: added the link
[Edited on 17-4-2018 by Pumukli]
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DIBALL
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| Quote: Originally posted by Pumukli | In Scr0t's pirrolidine synthesis there is a lot of turpentine, a small ammount of spearmint oil and no DMSO - although the reaction time is 20 hours
at reflux temp. (around 160 C) and he had had solubility problems. He suggested using a small ammount of DMSO to help with the solubility though.
[Edited on 17-4-2018 by Pumukli] |
I think I try to do it, like he did. Don´t think the DMSO will help with the solubility, since it dissolved gylcine really badly. But the reaction
worked perfectly fine without it dissolving. Also I think that this reaction will proceed a lot faster.
| Quote: Originally posted by Pumukli |
On the other hand I can't really help with the side reaction, the reddish color of phosphoric acid soln. or the mini explosion. Btw. wasn't this later
one caused by a simple mechanical blockade of the vapour path in the condenser? Was not this blockade caused by (methyl)ammonium-carbonate build-up?
[Edited on 17-4-2018 by Pumukli] |
The vapor which condensed, build up these crystals over time, so that they blocked the whole reflux condenser and the gas couldn´t escape anymore.
Than the stopper flew out of the flask with a small bang. How do you assume, that it was (methyl)ammonium-carbonate?
I have put this reddish liquid in the freezer for one hour and it was syrupy. Normal water in this amount would´ve be frozen in 10 minutes.
I let it in the freezer now and then try to filter.
But has anyone an idea, if there was (or could be) a reaction between the DMSO and glycine? Didn´t had advanced synthesis chemistry in Uni...
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UC235
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| Quote: Originally posted by zed | I've seen those videos. Copper Carbonate works poorly. Copper Chromite works very well. Seems to me Doug's Lab has a nice procedure.
I mentioned this because Nicotinic Acid, seems structurally quite similar to the imino-acids we are attempting to decarboxylate.
Copper Chromite accomplishes this decarboxylation, at right about 100 C.. A much lower temperature than that employed in most procedures.
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Copper Chromite is specific for aromatic COOH groups in the presence of pyridine-like ligands. The traditional option is refluxing quinoline and
copper powder. I don't believe it will work on glycine.
Doug's Lab procedure is mine from Prepub, tacked onto Magpie's pyridine thread, which is itself a modification of Ordenblitz's procedure.
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zed
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I'm suggesting that Copper Chromite might be effective for decarboxylating Amino-acid Imines.
[Edited on 18-4-2018 by zed]
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Melgar
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I mentioned using DMSO + spearmint as a catalyst once, but eventually realized that DMSO was an oxidizer under high-temperature conditions. Try using
propylene glycol, if that's what you're trying to do. Maybe methylsulfonylmethane? Or even naphthalene? Or cetyl alcohol? The solvent barely
seemed to matter if there was spearmint oil present.
The first step in the process of learning something is admitting that you don't know it already.
I'm givin' the spam shields max power at full warp, but they just dinna have the power! We're gonna have to evacuate to new forum software!
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zed
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Napthalene might be a good idea.
In these days of difficult and expensive, solvent purchase, I can buy Napthalene for about 4$ per pint-pound.
Hadn't thought of it, and I like it.
Stinky though.
In the past, I have considered the use of Camphor.
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DIBALL
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| Quote: Originally posted by Melgar | | I mentioned using DMSO + spearmint as a catalyst once, but eventually realized that DMSO was an oxidizer under high-temperature conditions. Try using
propylene glycol, if that's what you're trying to do. Maybe methylsulfonylmethane? Or even naphthalene? Or cetyl alcohol? The solvent barely
seemed to matter if there was spearmint oil present. |
Right, I thought that something like that might be a problem...
I already tried PG, but someone said, that this could react too.
I will do it the classic way with turpentine. This shouldn´t be a problem?
Also I think, that methylamine is quite soluble in some things like DMSO and a lot of it stayed in solution. I´ll try it the next days with
turpentine and HCl solution. The mystery solution that I got from the phosphoric acid reaction, was no surprise, just phosphoric acid...
Naphthalene is a bit too much paperwork, where I live...
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zed
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Naphthalene purchase requires "paperwork" where you live?
Here in Oregon, last month, I saw it both at The Dollar Tree and Walmart.
About $4/pound, OTC..
Tell me more, tell me more.
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DIBALL
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Good news everyone!
I had 2 productive days and a lot new and interesting was witnessed!
So I tried it with turpentine and was disappointed, that it was a lot slower than DMSO! 50mL of it and 5g glycine with 8 drops of spearmint and after
an hour only about 30% reacted.
But I realized, that it already started to bubble (a tiny bit) before even heating! Also I thought, that it reacted better at a lower temperature,
since only a few bubbles came over when boiling, instead a lot when I started heating, but it was probably due to the heating air.
This let me think, that I should try it in water. So same setup and 50mL of water, which almost dissolved everything.
Almost no bubbles came, when it was boiling, so I stopped after 1h. Then I added, after it was just warm, some NaOH solution and it started to bubble
(keep that in mind). But it just made me mad and didn´t notice, what it actually meant.
Then I got pissed (not the Australian kind) and thought "screw this!" and added 200mg of basic copper carbonate, water, peppermint and glycine.
After one hour no change...
I left it over night to cool and the next day I was surprised, that half of the flask was full of white solid. Since the glycine dissolved almost
entirely and the copper carbonate was blue and only 200mg, I thought, that some reaction has happened. Then I realized, that zed said, that it might
be methylamine carbonate! It also clogged my condenser and aside glycine it couldn´t be anything else! If it was ammonium carbonate, the bubbles
should have been more vigorous during this reaction (which didn´t happen this time), due to the methane formation!
I thought, that it should be a positive, if I add some NaOH and it bubbles. So I did!
Some drops (I already stepped away, because of my high expectations) and nothing happened... added till pH10... nothing.
Then I added till pH 14 and still no gas (but the insoluble solid disappeared!). I hooked it to the bubbler and no bubbles...
Then I smelled it and it smelled like ammonia and bit fishy!!
I was finally happy, that all reactions since the first spearmint try were a success! While I was cleaning the flask I realized, that I could´ve
heated it, but it was already gone.
I restarted with 40mL DMSO, 8 drops of spearmint, 4g of glycine and a 20mL 5% HCl solution. Since I wanted to treat myself for this discovery, I
celebrated this, by adding a stir bar for the first time during this research.
I set it to stirring and brought it to reflux. A lot of bubbles arrived during the refluxing and it kept up, almost constantly, until only 20% of the
glycine was left (after 30-40min). I stopped heating, because the condenser was about to get clogged once again...
It was brilliant to watch the glycine bubbling, even though it was under 100C! The reaction just wants to happen! I cooled it in an ice bath and on
the flask sides a lot of crystals appeared! A strong ammonia sent was noted after opening the flask.
I added NaOH solution and the sent got stronger! I reattached it to the bubbler and a few bubbles appeared then! After reheating, the bubbler received
more bubbles than usual.
I changed to distillation and decanted the glycine that didn´t react. I heated the solution and since I didn´t want any decomposition, I applied a
weak vacuum (260 mmHg). at around 80C vapor came over, but started to solidify on the condenser. I stopped the water circulation and the problem
didn´t appeared anymore. The temperature rose soon and I turned the vacuum off, to see the "real temp". It was 110C and the steam dissolved the
solid. I stopped the vacuum, after the temp rose again for a bit. And was left with 14mL of a two layered solution, where the upper one, had particles
floating around. With a bit of smelling, I assumed, that it was probably peppermint and a bit of DSMO with out desired substance.
The heated flask was cloudy with fine sized particles (not like glycine!).
I´m thinking about filtering this one and the other one is in the freezer. After one hour at -20C it is still a liquid.
Conclusion:
Everything works as we expected! The failures actually have lead to the insight, what was actually going one and how much is actually possible!
The decarboxylation appeared as predicted, but mostly the methylamine didn´t gas out, instead got stuck in the solution as methylamine carbonate...
With NaOH it is possible to gas it out, but due to the great solubility of the methylamine, it stayed in the solutions. The best way to separate it,
is distillation or crystallizing it, which isn´t really an option in DMSO due to the high melting point. With the copper carbonate method it should
be possible, if you get rid of the copper or react it with NaOH and boil it, till most of the gas is out of solution.
So the methods, that should be possible:
1. Peppermint, solvent (preferably DMSO) glycine, reflux → bubble in HCl and then distill the solution of the initial beaker → react with NaOH and
bubble in the HCl solution → evaporate → purify?
2. Water, basic copper carbonate, glycine → let it react under reflux → cool it down, so a lot precipitates → filter → get rid of copper
carbonate → purity?
3. Since the first tryings of our research worked, but not qualitative (or the supposed ammonium chloride was just the methylamine carbonate). I
suggest, that the NaOH solution is added slowly drop wise and not whole!
I think, that the excess of NaOH lead to the demethylation of the amine! But just a guess...
Okay, since I didn´t have done a qualitative test of the products yet, we shouldn´t be too euphoric (or maybe it´s just me  ). But I couldn´t find any reason, why it should´t work. The next days I will do
the final steps and try to find the purity of it.
So what do you guess? Any additions? You noticed something, that I did not? Also it would be great, if some people around here, could recreate
my processes and verify (or not) our findings!
In a country, that needs paperwork for methanol, because some stupid drunks used to drink it or sold it as spirit, cause they were too cheap and too
dumb to distill!
[Edited on 1-5-2018 by DIBALL]
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