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Preparation of crystalline THCA

1. Extract fresh plant material with 0.1% acetic acid v/v in hexane. Filter and remove solvent by rotavap. The purpose of the acidified extraction solvent is to minimize ionization of the cannabinoid acid which would hinder subsequent purification steps

2. Pass the THCA rich solution through a column packed with Sephadex-LH20, eluting with 2:1 chloroform/dichloromethane. Collect the THCA-rich fraction.

3. Redissolve the crude THCA in methanol, filter insoluble material, remove solvent with rotavap

4. Redissolve crude THCA in pentane, filter, and rotavap to give THCA crystals

* All solvents and chromatography materials were obtained off the shelf from a local lab supply shop. 10L rotavap obtained from BHOgart
 

G.O. Joe

Active member
Veteran
* All solvents and chromatography materials were obtained off the shelf from a local lab supply shop. 10L rotavap obtained from BHOgart

I know I'm not the first to see this patent for this and copy the procedure, has anyone else had success with this?

What was your column loading ratio? What was the flow rate and how many column volumes of solvent were necessary to start and complete the elution of THCA, and how long did that take? How much did the Sephadex swell with that solvent and how much did it take to fill the column and how much did that cost? How is the Sephadex cleaned for reuse?

The patent, I do know is US 7,700,368. Those details are not in it.
 

G.O. Joe

Active member
Veteran
Is someone getting quotes on the sort of shiny new industrial gel chromatography system you guys would want? We won't tell.

The patent specified a column 1.5 meters tall filled to an unspecified height with 400 g. of the Sephadex, loaded with the dissolved extract of 100 grams of something. Let's say it was 20 grams of extract - 1:20 column loading is not bad at all. But, the LH-20 product instructions suggest a flow rate of 1-10 cm./hr. Compare this to the level of detail in El-Sohly's 6,730,519.

There are faster, dirtier, much, much cheaper methods that scale up well.
https://www.erowid.org/archive/rhodium/chemistry/equipment/dry-column.vacuum.chromatography.html
 
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I guess THC can be taken up somehow by mucous membranes, analog to Sativex.

I wonder what the effect of eaten THCA is?
Has anybody tried? Is it psychoactive or not? Does it affect pain?
 

oceangrownkush

Well-known member
Veteran
Couldn't you just purge it like BHO? I know people use Hexane to make extracts and don't spend 12k on their desiccation chamber. Has to be an alternative to the rotovap.
 

kaosisallwesee

New member
Never mind, sorry can't figure out how to delete my post, didn't realise what you were saying, 12k was the chromatography set up, 8k was the desiccation set up
 

kaosisallwesee

New member
A rotavap and desiccation chamber are completely unrelated...

I understand what each is for. I, again, haven't figured out how to edit or delete. And they're not completely unrelated, they both remove solvent, just in different applications with different requirements.
 

Pangea

Active member
Veteran
Ive read them having purified THCA, but not large crystals, there a pic from the cup that shows it: http://marijuana.blogs.pressdemocrat.com/10495/great-finds-at-the-emerald-cup-2015/

There is another group that posted to the isolation thread, CaliLabs, that has them formed but not sure if for sale. They have an IG pretty sure its calilabs.

There are others right behind, though, its very simple.

Use a narrow, deep vessels, like graduated cylinders, or even test tubes for smaller amounts. Leave roughly half the depth unfilled for head space evap room. 30g of unpurged oil in a 60ml vessel will produce crystals within 3 weeks at close to room temp, a loose lid may be necessary.
 
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