Preparation of crystalline THCA

[live resin]

Pangea, didn't see a pic of that 99.99% THCA. And THCA decarbs at ambient temp, how can you get 99.99% by letting it decarb for 3 weeks??

Slower cooling during recrystallization = bigger crystals

To produce this product commercially one needs a massive outdoor crop that can be harvested early to minimize decarbing.

 

[Pangea]

The caption on the site linked to says 95%THCA, I cant check their instagram, so I didnt see any other pics either, they might have some big crystals.

The solution can contain THC, but surely there is a level at which it will hinder crystallization of THCA. The decarbing action at ambient or near room temp is extremely minimal and probably slowed more by being dissolved in such a solution. You wont get 99.99% large crystals of the first "seed" creation stage from raw bho, but further recrystallization will. I'm going say with a proper set up one could quite easily isolate most of the THCA out of a BHO solution, but just by letting it sit and with no proper tools and rudimentary understanding 2-10% will be normal.

Also, just keep in mind how much THCA vs THC there is regular processed BHO, its minimal even when undergoing heating and vac purging.

I will agree though cooler temps will evap slower and most of time produce a better crystal. Slightly early harvest would be better than a later one, but its pretty rare from what I know, for a live plant to have any appreciable levels of decarboxylation, best bet is to harvest right on time for max levels of THCA and terpenes.

 

[live resin]

In preparation of crystalline THCA, terpenes and any other compounds developed in the last week before harvest are just contaminants which must be removed by chromatography.

And I would do the primary extract with hexane slightly acidified with glacial acetic acid instead of butane/propane, less decarbing of the thca

 

[Daub Marley]

guildextracts is calilabs, or at least they are partners

 

[SoufLondon]

In the 90s i knew i guy who made thc-acetate cristal. He was doing a phd at the time and had access to a pretty decent lab! Not sure how its made. Racy stuff, makes you paranoid! Not a particularly nice high!

 

[Pangea]

Cool Daub, thanks for the info.

Live resin, you dont need to remove any contam with chromatography to purify/isolate THCA if you use seed crystallization and re-crystallization techniques, the nature of crystal formation will result in a pure substance.

I'm reminded of GW's analogy of the fish and fish net.

 

[Gray Wolf]

In the 90s i knew i guy who made thc-acetate cristal. He was doing a phd at the time and had access to a pretty decent lab! Not sure how its made. Racy stuff, makes you paranoid! Not a particularly nice high!

We make THC-Acetate, though it isn't crystaline. We also regularly taught others to make it class.

We do so by refluxing an absolute in sulfuric acid and acetic anhydride.

Without exception, every student and test panel that tried it, loved it, including me. I on the other hand, don't find straight THC all that exciting.

 

[G.O. Joe]

Has that preparation been analyzed yet for purity and identity?

 

[live resin]

Live resin, you dont need to remove any contam with chromatography to purify/isolate THCA if you use seed crystallization and re-crystallization techniques, the nature of crystal formation will result in a pure substance.

I'm not SC Labs. Obtaining pure acidic cannabinoid standards is more difficult than buying highly watch/regulated chemicals like acetic anhydride.

If you're saying I can isolate crystalline THCA from a standard hydrocarbon extraction by recrystallization instead of chromatography please tell me how.

I don't think the staff scientists at GW Pharmaceuticals would have gone through the trouble of developing chromatography methods for cannabinoids if isolating pure THCA was as simple as recrystallization.

 

[Pangea]

There are many reasons for developing chromatography methods for isolating cannabinoids, I am sure even if GW Pharm were aware of the simplicity involved in a method like ive shared they would still pursue and research other methods, there are utility and merits to different paths.

Ive shared it a few times, but guess I can be more detailed.

The recrystallization for purity part is pretty standard, the initial crystallization part is the first hurdle and just as simple. Its actually easier than making traditional BHO as it involves less steps. Instead of spreading thin and purging, collect it in a container/vessel that allows for slow, controlled evaporation, depth of the solution vs surface area is a important factor as is the headspace and lid for evaporation. A container like a graduated cylinder is ideal or a regular 250ml mason jar filled at least half full work as well. The larger the surface area the easier it is for the solution to crash, and also has other limiting factors. The solution viscosity is important as well, I vac my collection chamber down to -20, there is no liquid tane, I cannot pour out the solution, I scape collect it, but its basically like a No 1. maple syrup consistancy, very liquidy, very terpy, glass baster/droppers work well to transfer.

So recap,

1. Collect bho into proper vessel.
2. Store in proper area; consistent temp, limit light, limit vibrations, limit disturbances.
3. Wait until satisfied with crystallization amount.
4. Pour off un crystallized solution into new vessel to further form crystals(depends on state of solution) or pour/spoon out and treat remaining solution as if it was just extracted, so either vac purge or decarb for edibles.
5. Carefully collect crystals from the bottom of the vessel(probably where a jar has a advantage over a skinny cylinder)

I've been able to grow crystals in little 2.5ml vials with high terp varieties after they have been vac purged, just by leaving the lid loose.

I've had a crystal in a sealed solution of RO water since I first collected them, it hasnt changed. Ive had a few in indirect sunlight for 60 or so days with no visible changes. They are quite stable.

I am excited to see some really large crystals, they're going to look very cool!

 

[weedaholic721]

I thought some pictures might inspire more interest into this topic. These are not my pictures and hope it is ok that I post them. The pictured THC-acid is by guild extracts in collaboration with calilabs. I am assuming from looking at older pictures that they are using a method similar to yours Pangea, however there is very little info given.

 

[Pangea]

They are the only guys following me on IG, so its my assumption as well.

Thanks for sharing the pics, they look solid! wonder what they're selling them for?

 

[Gray Wolf]

Has that preparation been analyzed yet for purity and identity?

We ran it through our GC and note the THC peak shifts to the left, but not other remarkable changes.

 

[heady blunts]

 

[live resin]

We ran it through our GC and note the THC peak shifts to the left, but not other remarkable changes.

Exactly how are you using GC to quantify acidic cannabinoid levels? I assume you're using FID which decarbs the sample

 

[Pangea]

Restek has shared a method to use FID to quantify cannabinoid acids:
http://blog.restek.com/?p=15135

 

[G.O. Joe]

We ran it through our GC and note the THC peak shifts to the left, but not other remarkable changes.

I still think years after the THC acetate discussions that refluxing THC with any concentrated sulfuric acid in organic solvent is a bad idea - definitely not something to teach unless the method is proven by analysis. Maybe bad idea isn't the right phrase and calling it THC acetate may be technically correct even, but if the product is the other isomer, then it should say so on the tin.

Labs probably wouldn't have a d8 THC acetate standard or feel like making one but the workaround is obvious. Hydrolysis of suspected d9 THC acetate with refluxing alcoholic KOH would of course give only the d9 isomer back, which the GC could compare to genuine d9 THC. This assumes that the GC method is proven to separate the two isomers as well.

 

[live resin]

100g plant material to (2 x 1500 mL, 99.9:0.1, v/v) n-hexane/glacial acetic acid

Dissolve crude product in 20 mL 2:1 chloroform/dichloromethane

Low pressure glass column 1560 x 24 mm

400g Sephadex LH-20; stationary phase/sample 30:1.

Each collected fraction is 50 mL

 

[Old Gold]

^ That was pulled from GW Pharma patent, correct?

 

[live resin]

^ That was pulled from GW Pharma patent, correct?

No that stuff wasn't in the GW patent. This is from people at the University of Mississippi that were replicating the experiments and reviewing these patents