THC isolation from crude CBD oil


Does anyone have any insight on how THC-free crude is being made? I know I could just dilute it to become compliant but what are some other ways?

I’ve seen posts on using flash chromatography for using distillate but would this be applicable to crude?


“crude” implies no additional processing steps, so once you’ve diluted it in solvent and run it over a column it’s no longer “crude”.

sure, you could call that semantics, but I think there is vital information missing here. do you have any additional details? can you point us at examples?

Edit: perhaps very special genetics?


Sorry I should have been more specific. I’m seeing alot of ethanol extracted THC-Free CBD crude oil being advertised. which allows it to be compliant and ship across state lines.

Extracting compliant CBD hemp biomass generally will cause you to test high for THC. I’ve seen methods for isolation of THC out of CBD distillate on here but haven’t seen much on the topic of crude oil being able to use chromatography.


ah, that would then be a truth in advertising issue.

it’s either “crude” or it’s been post processed. chromatography IS post processing. so the thc free “crude” you are seeing advertised is not in fact crude, or is not in fact thc free.

yep. given that the synthase enzymes for THCA and CBDA are evolutionarily related to each other, and have been shown to produce each other’s products in-vitro, it is pretty unlikely that genetics will get you there. but artificial selection is a very powerful tool, especially if combined with a mutagenesis strategy. so I wouldn’t rule it out entirely.

any chromatographic step that can separate those two very similar molecules from each other, is also going to separate them from pretty much everything else as well. Once you separate the cannabinoids via chromatography, you have also separated them from pretty much everything else in the jar.

it’s no longer crude, it’s isolate.


On the topic of chromatography… Why not isolate the thc and then flush the column and remix all your fractions. Seems like youd be pretty close to the oil you started with minus the thc.


can’t argue with that logic :slight_smile:

not sure it’s makes any sense in the real world, but it would seem to be a formal solution to the OP’s question.

a THC(A) antibody based affinity column would seem like another. assuming no cross-reactivity to CBD. everything but the THC(A) should pass straight through. not cheap though.


Why not just crystallize out the THCa? If you leave the crude undecarbed and pick a suitable solvent I would think that would be an easier method and much cheaper than using a chromatography machine.


I was actually thinking about that after I posted this. I’ll try to run an experiment and let you know how it turns out


the CBDA would seem more likely to ppt than the minor cannabinoid in the mix (the THCA). I’ve not crystallized CBDA, but my understanding is that it does crystallize. given the relative saturation levels, I would expect it to crash first.

I’m still of the opinion that we may have an oxymoron here…


I don’t have a study or anything on hand but I was under the impression that is does not crystallize.

By oxymoron do you mean that choosing a very low thc strain is the solution?

Yes, that is A solution. Your looking at this from a genetic standpoint, im asking this from a chemical engineering viewpoint… what would our best methods be to isolate thc out of crude efficiently from a production standpoint.

I can’t rely on every grower to source those kind of genetics, not yet at least :upside_down_face:


By oxymoron I mean something that cannot be.

Some might give “military intelligence” as an example…

It is either thc free, or crude…


The only two methods of isolation I am aware of currently are chromatography and crystallization. The latter seems to have been the preferred route in the hemp industry hence the preponderance of CBD isolate on the market. Fractional distillation can provide a little help sometimes but it can’t do a clean separation unfortunately. At least in my experience anyway. If it’s possible to crash out the THCa before getting to distillation that would be excellent.

It certainly warrants a small experiment to see what happens. I have never seen or heard of CBDa crystallizing but a simple experiment would put the matter to the test. If it doesn’t work then we know that chromatography is the method needed to get THC-free distillate. It would be interesting to hear from some large scale producers to see how they approach this given the difficulties in scaling chromatography up to an industrial scale.


no experience with it…but certainly hear that CBDA does crystallize. rather surprised THC doesn’t, but that’s probably why I’m not a chemist…

A purified cannabidiol (CBD) extract and/or cannabidiolic acid (CBDA) extract is isolated from industrial hemp and comprises less than 0.5 wt % organic impurities as measured by HPLC and 1H NMR spectroscopy exhibits no detectable peak at 4.07 ppm as measured by 1H NMR spectroscopy. The CBD and/or CBDA extract is in crystalline form.

Have we decided whether post processing crude to be THC free still leaves the OP with “crude”? I can’t see how it does.

Is it relevant? Not sure about that either. @D_Mendeleev?!?

maybe it’s thc free Erl?


So after reading Robert.August’s IG posts it appears that he has adapted his own twist on an old patent to achieve CBDa crystallization. It appears from the chemistry discussion in the IG post referenced in the Future4200 thread that it should crystallize easier than THCa so I wonder why more haven’t commented or noted this experience. If anything it appears elusive to many. I guess the question becomes, which crystallizes easier in practice, THCa or CBDa? Can anyone with experience with this chime in?


Cbd is easier to crystallize in my opinion. Its obviously more easily crystallized in cbd oil. Crystallizing thc from cbd oil is not feasible.


Yeah I have seen CBD crystallize with very little coaxing but no experience with CBDa crystallizing.


I think we’re getting caught up over semantics. I now see what you are saying about my definition and i’ll agree that yes since its been processed from its no longer technically crude. I agree I don’t think its relevant either so we can call it Full Spectrum Etoh Extract with thc isolated if that helps clarify things?


Would you elaborate as to why it is not feasible?


Crystallizaitions are exceedingly difficult if the concentration of the compound of interest is too low. Also cbd and thc are so similar in molecular structure it is challenging to crystallize unless one of the two is in a vast difference in concentration, ie One very high, one very low.


So I guess that leaves chromatography as the only method of isolating CBD/CBDa outside of crystallization. Is that how industrial level facilities are getting it done for their THC-free distillate? If so it’s not surprising that isolate is so popular, much easier to make on a large scale I would think.