Sciencemadness Discussion Board

Input on vacuum distillation of THC

vcmingvltles - 7-6-2017 at 02:36

Hi everyone, just trying to get some input on my setup and procedure as everything I am doing is trial and error. I am distilling THC to use in the treatment of cancer.

Equipment - all joints b14/23
250mL round bottom flasks
300mL Liebig condensor (60C temp)
receiver adapter
vacuum pump (25 microns)
magnetic stirrer hotplate

First freezing IPA and the plant matter, followed by two alcohol washes, filter off then boiling off the IPA left me with approx 50mL of black oil.

First attempt I had no vacuum grease so wasnt achieving vacuum in the flasks and heating over 120 C began smoking in the flask, bad.

Second attempt with the grease appeared to start well, however without any capillary tube or magnetic stirring the bumping was quite aggressive and appeared to be throwing the liquid up the boiling flask adapter and into the condensor however the oil that did come over was a heck of a lot cleaner in appearance then the black sludge in the boiling flask but still contaminated. No smoke in the flask even turning the temp up to max on the hotplate (no mag stirrer yet).

Third attempt had vacuum leaks and could see smoke form in the boiling flask only to rapidly be sucked out and down the pump, great. Using an oil bath now to keep heat transfer more stable.

Fourth attempt couldnt identify any vacuum leaks, using a magnetic stirrer now so no bumping in the flask, still no product distilling, using an IR gun for temp at the moment about 220C in the flask.



I'd say I've already reduced the volume by about half in the boiling flask, have I already boiled out all the THC and only waste is left? Seems like alot but I really had no idea what to expect.

I dont believe theres any vacuum leaks but its quite strange, the temp of the condenser is 60C, the boiling flask is 220C, but the temp in the adapter in between is around 40-50C, I can see it climb and fall but only in small amounts and not matching the thermostat turning on and off. I believe the temp should be matching the vapours that should be coming through.

Its just strange its like the temp in the flask is not climbing the glass, are the joint sizes too small restricting the vapour pressure?

Just after some input from anyone experienced in the procedure to give some input, like to know if I'm doing something wrong or if I'm expecting too much or if I have forgotten something glaringly obvious.

Much appreciated, if I need to provide any more information just ask

IMG_0314.JPG - 212kB

alking - 8-6-2017 at 09:29

Looking at your picture I don't really see the problem? It looks like you have plenty of oil in the receiving flask. Based on what you wrote I expected there to not be anything there. Are you just surprised there's so much left in the pot and nothing more is coming over?

If so you should keep in mind that what you are distilling from is quite impure. It's an alcohol extraction, which is very non-selective, and it's black so you know it can't be but so pure. I would try winterizing the oil before distilling it next time, that will get rid of a lot of the higher boiling fats and waxes which should make the distillation a lot easier.

Also are you running the pump throughout the whole distillation? It kind of sounds like that based on what you wrote, but that's really not necessary and will lead to a damaged pump and loss of product. You should get a ball valve, if you have no leaks once you get to a certain pressure it should hold there. A ball valve will also allow you to control the vacuum power which will allow you to safely pull a vacuum without bumping or boil overs from pulling it too quickly. If it doesn't hold, and you have no leaks, then it means you have some lower boiling components left which are limiting the vacuum, you have to boil those off before you can increase the vacuum to a necessary level to distill the THC. If you run the pump to pull them off then you're just sucking them into the pump contaminating your oil, degrading the pump, and ultimately limiting the max vacuum it's even capable of pulling.

You might also want to just forgo the liebig and connect your 105 to the 75 directly and submerse the receiving flask in a ice bath or something. If you have no solvent or lower boiling components then the vapor pressure will never build up enough to need a condenser.

[Edited on 8-6-2017 by alking]

Alice - 8-6-2017 at 09:50

Have you ever measured what vacuum your pump can really achieve in a blank run?

binkhash - 30-6-2017 at 10:59

It looks like you have many passes to complete before you are going to be able to distill out the THC.

Alcohol extractions are dirty. I would definitely filter, winterize, scrub, and then filter again, (preferably with a filter medium)your original 50mL oleoresin before you attempt to distill it. This will help to remove some of the inactive compounds such as chlorophylls and waxes. The idea is to remove as much "junk" from your oleoresin before distilling it in order to reduce the number of compounds in the bp band, this will make it possible to actually distill out the cannabinoids.

Just curious, why aren't you using a short path distillation apparatus?

Also, for safety and sake of your pump I would rig up some sort of cold trap. ;)

binkhash - 30-6-2017 at 11:05

Also, I would distill your oleresin in fractions. This is the only way to get to to the point where you can actually distill out the THC. Otherwise all you are doing is refining your oleresin while simultaneously contaminating your product.