Newb; some questions about isomerization of pure CBD crystals I haven't really found an answer to

Hi, new to this community, hoping I’m not doing anything wrong; if so, please correct me! Some lab experience, but none with cannabinoids or anything analytical. Just private use.
I’m pretty lost with above questions, and I’d seriously need this stuff for medical reasons.

As it is pretty much impossible for me to get a hand on normal weed, I thought about isomerizing CBD to THC. I’d buy 99,9% pure CBD crystals, and try to convert them to THC.

Considering availability, I’d have two options:

a) Use 0,005M (0,005N)? hydrochloric acid in 99,5% Ethanol. Sure less dangerous than option b. I’d dissolve the crystals in Ethanol, add the acid and (kind of) reflux (I’m afraid for ~19 hours? Can it be done quicker?) Reflux DIY with kitchen utensils mostly. As I understand it, that will only yield 60% THC, coming from a THC-free CBD powder. Am I right with this? Also, what happens with the other 40%, will they remain as CBD or degrade/get lost or whatever? I would rather have a higher rate of THC to CBD than 60:40. How much Ethanol would I need to dissolve 1 gram of CBD for the izomerisation process?

b) Second option would be petroleum ether with para-toluolsulfonic acid (would that also be 0,005 N?). I read it would yield about 90% THC which I would greatly prefer, because of price and THC:CBD ratio, but it sounds really dangerous. Luckily I wouldn’t have to extract the CBD, I’d just dissolve it in petroleum ether, add the acid and reflux for… 1 hour? two hours? Can you guys tell me how much p. ether I would need to dissolve 1 gram of CBD? If it is lots, I’d reflux as shortly as possible, neutralize and let it evaporate by itself in free air. (If I have the guts.)

Thank you so much! :slight_smile:


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You should look up a way to do this in the literature. Winging it will cause you to lose precious materials. Your other option is to seek out a synthetic chemist that will either offer you consulting services or kindly show you how to do it for free. That being said, the pTsOH will not come as a solution. You will need to know what stoichiometric amount you need per moles of CBD being used. You should also get some proper glassware so you don’t waste your time. If you find a proper procedure from the literature, you will have a known and published method to convert CBD to THC.


Thank you for your reply. I’ve been getting into this rabbithole for quite a while, and I find I don’t have enough resources for most of that. I’ve read a lot of conflicting stuff online. (There was a page about doing it with EtOH/HCl and petroleum ether/para-toluol… but there was a calculating error in the EtOH one, so I can’t trust the info on the other method :frowning: )

I have some equipment, but I don’t have a reflux device, for example. I’ll do a very, very crude test with very little CBD in a 15 ml Falcon tomorrow. I have some Falcons, a scale, some pasteur pipettes etc. left from my lab days. I will get some petroleum ether etc. resistant bottles and measuring stuff from a lab shop The reflux thing I’ll just try to wing (for the bigger amounts I would use a kitchen double boiler with a turned-over glass lid, either with or without a ventilation hole - I’d need to find out how much gas wants to get out and depending on that, either the hole or leaving some space for the gas; put ice on the other side of the lid so the solvent can drop back into the mix… oh well!)
If it proves to not be feasible with what I have and can get to know and get, I’ll just settle with vaping the rest of the CBD after some failed attempts and leave it at that.

I know this works in theory… I couldn’t eat for years, so when I drank a sort of Green CBD dragon it sometimes would get me high by way of my stomach acid, lol!


have you checked in the Data Dump?

or used google scholar?

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Etoh to CBD should be 1:1 ratio

Thank you, guys,

reading up on some stuff right now. I’m also sorry for unintentionally flagging some of your comments! I though I was saving the comments. Can I undo this myself?
Edit: Thanks Admin, sorry for being so stupid…

Read this:

The Organic Chem Lab Survival Manual: A Student’s Guide to Techniques
ISBN-13: 978-1118083390, ISBN-10: 1118083393

How did it go? Were you able to transform CBD into THC?

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Thanks so much, I’m a tiny bit smarter now. Even more questions arised, haha.

Sorry, this will be a long text!

Oh well. I don’t know yet; this was a test-run with a tiny, tiny amount, a lot of loss in the process and it was CBD in only 70% isopropanol with 1M HCL. (Just what I had on hand really). Solution had a pH of ~1 in the end, ended up using loads of sodium hydrogen carbonate to neutralize. Terrble fallout formed, I suppose it was NaCl. Great losses dividing them again, haha! Now those poor, tiny 100 micrograms of CDB I started with might be enough for one dose maybe. Haven’t tried yet, evaporating the solvent over night. Learned a lot today :D. Will report tomorrow.

@SuperCat: Really appreciate the infos! If you don’t mind or anyone else would be ok to answer my new questions… Next plan is:

This is based mostly on the Hemp Husbandry isomerization bit.

  • Dissolve 3 g CBD in 200ml (just an educated guess) petroleum ether with 200mg para-toluolsulfonic acidx1H2O.
  • Reflux for 2 hours. I made up a new plan: I’ve bought a 500 ml Schott bottle. I’d put it in a pot with water, sitting on an oven cloth so it’s not in direct contact with the heated metal. Screw on the lid the tiniest bit so that gas can evaporate (like for autoclaving) or just lay it on top of the bottle. Put an icepack in the lid. Regulate temperature to be the boiling point of the petrol. ether.
  • After ~ 1 hour, do that 5%KOH in EtOH test with a bit of the solution, keep on going till the test comes out clear.
  • Wash solution with 5% sodium bicarbonate (half the volume of my solution). I only have sodium hydrogen carbonate and am not sure which concentration to use. So I’d wash with 10% NaOH as suggested in the chemistry lab manual instead. Petroleum ether isn’t miscible with water as far as I know? Just making sure. Also, too much NaOH would be washed out in the next washing step with pure a.dest., I suppose? Would you guys just shake it up for a minute or something? After that, put lid loosely on the bottle.
  • I can’t afford a separation funnel right now, but I could also suck the upper layer out with a syringe or a 10ml pasteur pipette and transfer it to a new vessel.
    -Let the solvent evaporate, do stuff with the THC.
    Or something like that…
    (Edit: corrected some illogical nonsense.)

twisti is a bot


Thanks, guys.

zip lock bags make workable sep funnels. cut the corner off, and pinch to control flow.

assuming your solvents don’t eat ziplocks.


That’s a good hack, thank you; I actually have some of those lying around. As I’ll use petroleum ether, I wouldn’t count on them not being eaten, though. But I’ve done that thing a lot (just not for this purpose), so I’m sure it will work in a lab glass botte. I have a 50ml perfusion syringe made of PP which will come in handy. That’s like 3 professional items already, lol. Both methods have their advantages! The original contraption would be the real deal, but god, that alone costs a fortune to me.

Maybe not?

That I could actually wing with my stuff. My biggest and most expensive problem is this reflux apparatus guy; hence the coffeemachine for outside to make it safer.

What do you think of this guy here:üler-Sets/89756-Schüler-Set+Destillation+mit+Stativmaterial.html
I suppose I’d only need a bigger bottle (500 - 1000ml) for this?

Just in to report twisti the bot was pretty high a couple of hours ago.

So to the rest of you: it worked! For the lot of improversation I had a pretty good result. Can definitely be improved. I used p-TSA in petroleum ether.

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Great to hear it worked. Was the small isopropanol and HCl test successful too?