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DMT Sublimation

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Trickster

Trickster

Esteemed member
OG Pioneer
Chemical engineer
I am working on a DMT sublimation project. A friendly glassblower can make a copy of Chemglass sublimator (see picture). As a coolant I can use ice or dry ice+acetone. I may even try liquid nitrogen, if necessary.

I am not sure how good vacuum I would need. For the moment my only source of vacuum is a water aspirator, but, if necessary, I can buy a rotary vane or membrane pump.

Does anybody know what pressure is required for DMT to sublimate? Does anybody have first-hand experience with sublimation? Any input would be much appreciated.
 

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Very interesting, but I highly doubt that one could achieve anything with a water aspirator. Its manometric pressure is like -3.2kPa, resulting in an absolute pressure of about 97% of that of the atmosphere.

To give you an idea, naphthalene has a vapor pressure of about 4Pa at 25°C, and this solid is quite volatile. Of course you don't *have* to reach its vapor pressure for it to sublimate.
 
If you're intending this as an ultra-purification step, it seems to me you could do better with column chromatography--at similar, or maybe lower, cost. Especially if the contaminants are unknown--and may have vapor pressures near the vapor pressure of DMT.

EDIT: Here's a nice tutorial, that shows a much simpler (and cheaper) glassware setup (see the slide show at the bottom of the page).
 
SWIMfriend said:
If you're intending this as an ultra-purification step, it seems to me you could do better with column chromatography--at similar, or maybe lower, cost. Especially if the contaminants are unknown--and may have vapor pressures near the vapor pressure of DMT.
Click to expand...

Indeed, I am trying to prepare a standard sample of pure DMT for future TLC identification of it in various plant extractions.

It seems that in chromatography the problem is basically the same. How do I know that in the crude mix there are no substances with similar Rf?

SWIMfriend said:
EDIT: Here's a nice tutorial, that shows a much simpler (and cheaper) glassware setup (see the slide show at the bottom of the page).
Click to expand...

I thought of that setup, but it has a major flaw. It is very difficult to disassemble without shaking off the product from the condenser. On the other hand, I may try this simple device as proof of the concept before spending money on something more expensive.

P.S. I am looking for a good vacuum pump for my home lab anyway.
 
Trickster said:
Indeed, I am trying to prepare a standard sample of pure DMT for future TLC identification of it in various plant extractions.

It seems that in chromatography the problem is basically the same. How do I know that in the crude mix there are no substances with similar Rf?
Click to expand...
Others have confirmed through gas chromatography and mass spectrometry that the large single fraction found using standard column chromatography methods, from a standard extraction, is pure DMT.
 
SWIMfriend said:
Others have confirmed through gas chromatography and mass spectrometry that the large single fraction found using standard column chromatography methods, from a standard extraction, is pure DMT.
Click to expand...

Still, my original question remains unanswered. Below what pressure DMT will sublimate?
 
I doubt anyone knows that info, if its triple point data is not published. You might try looking at data for similar molecules, if you can find it. Generally, I don't think people worry about that if they're trying to sublimate a material. Instead they create the best vacuum they can, and give consideration to staying below temperatures that would degrade their material.

Column chromatography allows for using UV light as an additional demarcation between fractions. You don't have that with sublimation. To measure triple points you need highly purified material...which is probably refined by CC :)

You might find triple point data here.
 
Thank you, Swimfriend,

SWIMfriend said:
I doubt anyone knows that info, if its triple point data is not published. You might try looking at data for similar molecules, if you can find it. Generally, I don't think people worry about that if they're trying to sublimate a material. Instead they create the best vacuum they can, and give consideration to staying below temperatures that would degrade their material.

Column chromatography allows for using UV light as an additional demarcation between fractions.
Click to expand...

Yes, but how would you detect which of the fractions is DMT? By comparing the intensities of zones luminescence? I would assume that under UV excitation some substances may emit visible light more efficiently than DMT, thus compensating for smaller quantities. I do not have access to GC-MS equipment.

SWIMfriend said:
You don't have that with sublimation. To measure triple points you need highly purified material...which is probably refined by CC :)

You might find triple point data here.
Click to expand...

Chromatography is definitely on the list of my future experiments. I have already collected a lot of data on detection and separation of DMT and other alkaloids.

But I did not discount sublimation completely, yet. As a physicist I love to experiment, so, once I have a decent vacuum pump, I will try sublimation anyway.
 
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