A (likely) unsolvable problem with ethanol extraction (keep them terps!)


You’re talking about high pressure extrusion correct? I am currently putting together an extruder system for liposome sizing and am super interested in terp separation via membranes- can you pm me some info if poss? I would love to test any theories you have and share the results. I’m so intrigued by this.


I’m pretty sure this can be done without any heating.


Regarding re-use of terpene-laden ethanol, y’all might want to take a look at the “Swiss cold water coffee decaffeination” methods. Wikipedia has a nice treatment…


Nitro-methane certainly sounds like “coolest” solvent to use lol. Just having nitro-methane on a package sounds badass lol. Maybe using it as some kind of crystalization solvent? But since pentane seems like everyone’s go-to it probably doesn’t make much sense.

Yeah I had thought of using carbon then “harvesting” the turps using subrcritical co2 from it. I’d be worried there’d still be a whack of alcohol left in the carbon, so might be counter productive for our process?

Also, thanks @back2thefuture you gave me things to ponder :smiley:


I had a thought of using a “pool” of something immiscible in ethanol but that would pull the turpenes. Then during the ethanol evaporation basically “bubble” the vapor through. Then do some kind of LLE on the receiving fluid to pull the remaining turps.

Not sure what would meet that criteria? I dont know enough about affinities to figure that out.


Cyclohexane and methanol are immiscible, I think. I see conflicting reports w regards to ethanol/cyclohexane miscibility.

Cyclohexane is pretty similar to hexane otherwise

Cyclohexane is not miscible with acetonitrile, dimethyl formamide, dimethyl sulfoxide, methanol, and water.

I can’t find anything ethanol is immiscible in, which is neat but perhaps another anti-ethanol point


Yeah I know lol, gonna have to get into some exotic/silicone based solvents methinks


I wonder if you had a crude solution of methanol and you added cyclohexane, would the biphasic mixture have one side that had a clean separation of product, or would both phases stay somewhat rich in the goods? The reverse is also compelling , if you pulled with cyclohexane instead of hexane, would washing in methanol be part of a working procedure?


The hexane methanol is pretty much the standard LLE Tek that people have listed on the site. Removes most need for solvent evap. I’m sure the cyclohexane would also be pretty effective.


Unless I put the $$ into membranes I think nitrogen pull beforehand or subcritical co2 are both gonna be the best candidates.

I’m still curious if there’s a theoretical saturation point with turpenes into ethanol. And eventually they’ll start excluding the turpenes in the initial pull. or, if in turn you could prep all of your ethanol beforehand to make a etoh+turp mix to use as your solvent.


Ethanol and terps azeotropically distil and that’s not going to change based on the ratio in liquid phase. If you had a gallon of terps and a liter of ethanol and distilled it the same ration of ethanol/terps would distil over until the ethanol was depleted. If you added a ton of terps to your receiving flask they would just mix endlessly


Ah makes sense, kinda what I figured, but hoped I was wrong :stuck_out_tongue_winking_eye:


4a mol sieves absorb alcohol, most of your terps are bigger than 4 angstroms I assume? Hmmm I’m not 100


Starting to sound like we should form a company and develop full filtration. :thinking:


Not sure if that was directed this way, but I’m into it :stuck_out_tongue_winking_eye: seems probable to be able to undercut the existing competition


3a sieves allow water to be absorbed.
Anything larger would not separate the water.
terps plus anhydrous EtOH…then through 4a would yes, contain terps only.

Water separation
EtOH separation
Terp capture

All in their right place.
That would Be pretty awesome and I can’t remember but terps can undergo signifant changes when in presence of oxygen, heat and a/b influence…again being lazy…just going off the top of my head right now.

My assumption would BE preserved terps as they are supposed to Be. Some thing like you know linólol turns into xyz etc etc —

Molecular weight of linalol is ALOT greater than water and ethanol.
So why not?


4a and higher definitely absorb water. Sieves absorb anything smaller than their poor size. So you can absorb water and alcohol and leave terpenes in theory… I’m not sure the cost efficiency compared to crashing them out with brine from the ethanol and separating them in a funnel, but I love your idea of adding a stage to automate it.

Does cannabis have isoprene in it in the final flowering stage in significant quantities? It’s smaller than the other terps

3a - remove water from the terpene alcohol
4a remove water and alcohol from the terpenes

I may have misunderstood a bit so forgive me if I’m just reiterating basic info lol


I’ve used zeolites before. I don’t think there’s going to be enough turpenes to actually make it through a column and drip down out the bottom. There’s so much surface area it’ll likely just sit in there. It’s also a massive amount required (10g zeolite to every 1g of alcohol)


“Temperature-Swing Adsorption”. Definitely would be using heat with this.
So reverse the filtration steps—terps first maybe or add demister pads / coalescing filtration as step one.

Water definitely is isolated and taken out and tsa methods are used in the fuel Industry — ive got design and implementation notes.
And this is good to know also:

@tweedledew I was gonna ask if there’s anything from the alcohol distillery side but you add not subtract.

I guess I don’t see why this wouldn’t work smaller scale too. I haven’t put much thought into it yet but it seems like this would be worth doing


We’re dealing with so very little turpene to ethanol ratio. I’m thinking for energy use we’re much better off adsorbing the turps. The energy required to do essentially a second distilling is prohibitive.

How about using AC. Then quick drying it under vacuum. Then using supercritical co2 on the ac to “recharge” it and remove the terps