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Reducing naphtha by distillation

Migrated topic.

Rick Sanchez

Rising Star
This is my first post as a full member so thanks to whoever did that. I can only hope that the spice gods have blessed you recently šŸ˜ Its nice to not have to post this in the welcome area lol . Anyways, pre-evaporating your saturated solvent before freeze precipitation is a process which I've found to be near essential if you want to get all the product out. Instead of just setting a dish in front of a fan in front of a window and trying to keep the cat out of that room all day, I wondered if I couldn't just use a small distillation apparatus like this https://m.ebay.com/itm/1000ml-Glass...9890?_trksid=p2385738.m2548.l4275&_mwBanner=1. The idea would be to pull a vacuum strong enough that the naphtha would evaporate at a low enough BP to not damage any of the spice. Ideally, this would leave a highly saturated solution in the heated flask while the receiving flask would be full of clean naphtha. If someone smarter than me can tell me why this won't work, please go ahead; it's the whole point I'm posting this instead of just going out and buying the glass.
Congratulations on your promotion! 8)

Distillation works, but try to use it preferrably with lower boiling naphthas. When the distillation temperature rises above 140 degrees celcius, noticeable amounts of dmt freebase start to co-distill. Perhaps using a distillation column could keep most of the dmt from distilling over.

Once, when distilling several batches worth of spent naphtha for reuse, I got hit by a cloud of dmt vapor when opening the distillation apparatus to top up the still pot with more naphtha. As I got a good whiff of the vapors, fractals broke out everywhere. It sure made all that shiny glassware suddenly look eerily beautiful.

I am not sure how much dmt will co-distill at lower temperatures in a vacuum distillation. In any case, when only distilling spent naphtha to clean it up for reuse, getting some dmt contamination into the "fresh" naphtha would not be a big problem.
Thanks for the reply! I think I might try a longer distillation with as low as possible of a temperature with a distillation column in place. Do you ever pre evaporate some of your solvent before freeze precipitating the product?

If DMT's melting point is 60-80Ā°C @ vacuum, if naphtha is below that, in theory you could use a vacuum pump to boil naphtha at room temp without the DMT evaporating?

Have you tried freezing the naphtha longer? A day extra, or two? Additional time to precipitate everything out..
It's not the melting point that counts per se, but the vapour pressure. If solid DMT is put into a vacuum at a temperature where its vapour pressure is greater than (or even close to) the pressure in the vacuum line it will sublime and disappear down your vacuum line. Make sure you use a freezing trap šŸ˜‰

Sublimation is a nice way to purify solids, if you have the apparatus.

Pitubo's warning about DMT co-distilling with higher-boiling naphtha is entirely valid.
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