Sciencemadness Discussion Board

Using liquid CO2 for active plant alkaloid extraction from the new "green industry"

RogueRose - 1-5-2018 at 08:47

I saw a post about getting samples of ethanol with some hexane in it and this stuff is supposed to be used to extract the good stuff from cannabis. The thing is, with all substances extracted with solvents, there are often some unwanted changes, tastes, smells, flavors from the extraction process and this is especially appearant in the essential oil markets and even edible oil markets where hexane is used to squeeze the last drop of oil out of the material. These oils are often reported to have different characteristics than the oils, from the same material, extracted by normal processes such as pressing, so there seems to be some negative consequences to using hexane in the extraction process.

Now IDK if using ethanol has many issues with extracting alkaloids or even oils, I suspect them to be much less than hexane, but still I've heard of much better methods for the target product for extraction and that is CO2.

I've read that liquid butane is also used. A glass tube is loaded with the "greens" and capped on both ends, then the butane fills the tube (in liquid form) and it dissolves the CBD's and THC. When drained it is then either evaporated slowly or sometimes flashed off in an open area leaving behind a sticky mess. This process also has issues of flammability and many fires, explosions and burns have resulted (I think one death by burns has been reported in Colorado).

Now I've seen some interesting experiments done with sealing liquid CO2 in glass tubing, sometimes called supercritical CO2. I think similar methods are used as an extraction technique with cannabis but produces the purest compounds with no sign of any contaminates after warming to 32F making it the cleanest process developed so far.

I'm wondering what pressure would be needed to contain liquid CO2 at room temp. I understand the the larger the diameter the glass tubing, the thicker the wall of the tubing needs to be (possibly by X^2 vs 2x) which is why it is much easier to store liquid CO2 in a glass tube (at room temp) in a small 1/4" tube than say a 1" to 4" tube, where the thickness needs to be MUCH thicker to handle the increased pressure. I'm not sure I understand this correctly (the physics part I mean), so if anyone could help me out here, I'd appreciate it.

Has anyone else heard of alkaloid extraction of any plant or cannabis's (or whatever THC/CBD - if it is alkaloid or what) by using liquid CO2 and have any information on this method?

Just as a note, my state just OK'd one of the largest research grow sites a few miles from me, an indoor facility grow area of ~20 acres in size + 10's thousands feet of processing & research! This is basically in the middle of a town! Now supposedly this place falls under state and federal regulation but I can not see how any facility needs that much grow room for "research", and they made sure there was plenty of expansion room on the 100 acre site. Some old convicts must be steaming mad or rolling in their graves for getting life (3rd strike) for single joint or less than a gram!





DavidJR - 1-5-2018 at 09:49

As far as I am aware, coffee beans are decaffinated industrially with supercritical CO2.

Tsjerk - 1-5-2018 at 09:57

I once got some liquid CO2 for a couple of seconds, at -56oC and probably around 6 atm. My goal is to extend that time by a lot, but I first need some motivation and a new piece of pressure piping.

Liquid CO2 at RT is going to be hard in any useful amount I think, if you try liquid at RT you can just as well go for supercritical.



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VSEPR_VOID - 1-5-2018 at 10:16

Here you go:
https://www.youtube.com/watch?v=-gCTKteN5Y4