Isolation of THCA

[Daub Marley]

I have a jar full of NaOH wash and nonpolar that I need to separate.. I believe it'll work.

It will. I've done it with pentane and a NaOH solution. I didn't take notes and didn't keep good control of the pH, but the yield seemed pretty small. I don't have any more fresh material though so I cannot repeat. All carboxylic acids regardless how hydrophobic it is will form a water soluble metal salt when mixed with a strong base.

 

[Old Gold]

Any idea if using sodium carbonate broke the molecule down as I theorized?
Looking back on G.O. Joe's post on page 1, he claims ethers ARE polar enough to extract cannabinoid-acids acids from sodium carbonate solutions, and possibly hydroxide solutions.
I need to retouch my chem knowledge, but I guess I can account for the weak base by using a slightly [or very?] polar solvent? So the stronger the base, the more nonpolar I would want to extract with?

 

[weedaholic721]

Carboxlic acid groups are the high priority group so THC acid is not a phenolic compound but a carboxyic acid..the position and shape of the cooh next to oh group allows for decarboxylation but the oh group will not affect extraction due to the OH hydrogen being more tightly bonded. At weaker ph only the COOH will be deprotonated but at higher ph both hydrogens would be removed. Not too familiar with the live resin process but if not dewaxed..the fatty acids should also be deprotonated, which could form an emulsion layer or effect precipitation

 

[weedaholic721]

Whill the side chains will make it much more nonpolar..THCacid is essentially a substituted salicyclic acid

 

[Old Gold]

Great info! I've heard THC be described as "terpenophenolic" but don't know the legitimacy of that term.
No secondary dewax was introduced after butane extraction, and yes, an emulsion is definitely seen on the top of the acidified solution that I believe contains my sought after compounds.

 

[weedaholic721]

Once decarboxylated THC-acid becomes the phenolic compound tetrahyrocannabinol ..I'm excited that I will finally be moving to a free state and will be experimenting as soon as I arrive..you are on the right track Old Gold and i think as long as use a dewaxed but not decarbed oil it should work.

 

[jazz messenger]

does anyone wanna talk about strong cation exchange resins for potential thc-a purification?

 

[icmagaccount]

^ Yes, however I am unfamiliar with resin form. Are the majority of the contaminants we are looking to remove positively charged? Should we consider filtering with something with an anion exchange capacity as well?

 

[SleazyWolf]

It really is! I'd been meaning to work an A/B extraction and post hopefully succesful pics for this reason for some time now. I got held up by a leaky sep funnel and countless other projects.

From what I understand, carboxylic acids form stable salts in basic solutions. Weak or strong base. Phenols however, will only form these salts when reacted with a strong base, not a weak base, such as sodium carbonate or bicarbonate.

In my original attempt, I used sodium bicarbonate to wash an organic layer of dissolved bho from live resin.
I originally did not realize that the carboxyl group sits right on a phenol ring in THCa. Given that I was unable to recover anything beyond a slight yellow oily residue, and nothing precipitated out of the water with added HCL (and then excess), I believe I separated my intended molecule, removing the carboxyl group from the phenol. Expertise opinions?

I have a jar full of NaOH wash and nonpolar that I need to separate.. I believe it'll work.
Then I'll get to work on recrystallization.

Great thread you guise. Stay innovative.

It will. I've done it with pentane and a NaOH solution. I didn't take notes and didn't keep good control of the pH, but the yield seemed pretty small. I don't have any more fresh material though so I cannot repeat. All carboxylic acids regardless how hydrophobic it is will form a water soluble metal salt when mixed with a strong base.

Is there a required post limit to PM people? I accidentally made some crystalline and I'm thinking its THC-a. They dissolved when I tried to wash the crystals with water. I would like to replicate this.

I have fresh material waiting to process, but I wanted to confirm my method before starting. I'm weary about sharing information on a public platform knowing that some people don't have the proper safety equipment, or common sense.

https://youtu.be/69dJzpw6ucI

 

[weedaholic721]

There is no better place to discuss then here, please elaborate. Hard to see much in the pictures

 

[Old Gold]

What's the scenario? Left behind from rotary evaporation?
Certainly could be. Carbpxylic acids with 4 carbon chains and shorter are water soluble, and as you get longer, you get less water soluble. I believe THC-A has a 5-carbon Chain

 

[SleazyWolf]

What's the scenario? Left behind from rotary evaporation?
Certainly could be. Carbpxylic acids with 4 carbon chains and shorter are water soluble, and as you get longer, you get less water soluble. I believe THC-A has a 5-carbon Chain

This is actually what was being added to the Roto. I noticed them when trying to add my solvent in. They clogged the inlet. Looked like glass shards. Had me worried for a minute. But they dissolved in water. In hindsight, I should have collected some for further testing.

Didn't make sense to me, but this was somehow a side effect of playing around with isomerisation. Used a non-polar solvent for initial extraction of frozen dry plant material. Added HCL and refluxed for about a hour. Neutralized with Sodium Bicarbonate while still warm and filtered with a 1.5u Buchner. It sat for a little while to cool after filtering before trying to add it to the roto. Crystals were found while adding solvent to the Rotovap.

Could they have formed from an A/B extraction? Or maybe I didn't reflux hot enough to degrade the THC-a? Or could it have formed from crashing? There might have been a little Ethanol left in my Buchners fritt before filtering. I didn't care that it wasnt totally dry because I usually wash the results from my solvent with ethanol once removed. Ill pay close attention to PH and temps the next run.

Questions for next time:
1. Can I use fresh frozen material for initial extraction in my non-polar solvent, or does the excess moisture foul things up for cryo temp extractions?

2. Would I be better off using sodium hydroxide in place of sodium bicarbonate? Or would that reaction be too hot and degrade the Thc-a?

3. Could HCL be used in place of acetic acid to acidify for initial extraction?


My plan was to acidify my non-polar solvent for initial extraction. Heat my absolute to below THC-a melting point, neutralize, filter, and then recover solvent. Collect crystals for purification. Anyone see any big red flags?

 

[Daub Marley]

Added HCL and refluxed for about a hour. Neutralized with Sodium Bicarbonate

You have made table salt (NaCl)
If you expose your material to temperatures over 40°C you will really start to degrade the THC-A, so don't reflux

 

[SleazyWolf]

You have made table salt (NaCl)
If you expose your material to temperatures over 40°C you will really start to degrade the THC-A, so don't reflux

Thats what I was afraid of, but I've never actually gotten it to crystallize before. For some reason I thought THC-a broke down around 70c, so I was thinking of heating to about 35c. But ill just skip heat all together and try separation with Sodium Hydroxide.

 

[weedaholic721]

Were you trying to isolate THCa or were trying to isomerize? For THCa from the method i posted, You did it backwards, the base is used to "pull the hydrogen off" of the -COOH of THCa . Then once neutralized with an Acid "adding H (+) back to the -COO (-), THCa should precipate out. If you evap after neutralization you will have salt in your THCa as well as possibly decarbing some of the THCa. Sodium bicarb is a weaker base; so the idea is it avoids extraction of phenolics (delta-9THC/CBD/CBN etc.) but dilute NaOH would work as well. Also reflux should be avoided all together.

Also, if you do not dewax your intial extraction from plant material, you will form an emulsion. Fats and waxes are also mostly carboxylic acids at the end of long nonpolar chains. This will form an emulsion layer when you add the basic aqueous solution to the nonpolar solvent containing your intial crude extract.

 

[Old Gold]

Perhaps excess NaOH removes the carboxyl group entirely?

 

[weedaholic721]

From what I understand, decarboxylation does not occur in basic conditions, but will in acidic conditions but I could be wrong on that.

 

[thegreenman91]

From what I understand, decarboxylation does not occur in basic conditions, but will in acidic conditions but I could be wrong on that.

Isn't extracted oil already fairly acidic?

 

[weedaholic721]

@thegreenman91 I can not say for certain as ive never tested the ph of extracts, however, THCa will be weakly acidic as well as other contaminants I'm sure. It doesn't appear to be high enough to do much naturally. Decarboxylation occurs mainly as a function of position of the carboxyl group and -OH. Heat and acidic conditions rotate the carboxyl group quicker meaning that its achieveing that position more frequently, thus a quicker rate of decarboxylation.

 

[weedaholic721]

It has been over a year since I posted this thread. It is amazing the advancements that have been made in such a short time. Thanks to all that posted and for continuing to bring higher purity cannabinoids to medical patients and informed adult consumers.

THCA, for me, gives the cleanest starting point base to then add modulators(Terps,CBD). I have not tried a true high purity THC distillate to compare. I'd be interested in hearing others thoughts who have tried both.