Preparation of crystalline THCA

[ClandestineChem]

Correction to last post:
Methanol is not soluble with hexane or heptane but is with water. However I still dont understand what you (Old Gold) did to get three layers of separation.

I took the liberty of visiting the pictures you posed and saw an unlabeled picture with a 1000mL beaker or flask containing equal volumes of a dark black solution and a gold solution. This looks to me like the THCA is in the gold layer and the THC and other trace cannabinoids are in the dark layer. Is this Naphtha and methanol?

Could you post a list of steps or the procedure you used? Even if its eyeballed math it would be greatly appreciated.

 

[Old Gold]

Reply:
After spending days searching multiple blogs, forums, and patents I am so happy that you directed me to this thread. Im also glad to see someone had a breakthrough and actually did it instead of just taking about it. I just wish I saw this sooner. I actually tried the a/b extraction that also didint work for you. I was disappointed when my n-hexane evaporated and nothing remained.

Could you please provide details about the most recent discover[FONT=Arial, Helvetica, sans-serif]y? I am a little lost on how you added only 1mL of acidic water and got separation. Did the THCA remain in the non-polar naphtha while the THC migrated into the polar acidic water?
How does the addition of ethanol or methanol work? Being both miscible with your polar and non-polar solvents wouldn't it just make for a poor separation layer? If not please explain.

Again, thank you for posting this. If possible I would like to direct message you but cant find how on this website (still new to icmag.com).
[/FONT]

I think you need 50 posts made to be able to send a direct message on these forums. I barely used half a gram of oil to begin with. Starting material was nugs that got overran with butane, and a little bit of plant material fell into the oil, so everything was redissolved in acetone and filtered. The acetone grabbed plenty of chlorophylls, anthocyanins, and other dark pigments/water solubles from the bit of leaf matter, leaving the plant material brown and dry. This oil was then winterized.

I used less alcohol than water (more was used to "wash" the crystal)....it didn't really create a poor separation layer the first time, as it was mostly water. On a larger scale than that, I didn't have success because of the miscibility you noted. Too much water was required, which caused impurities to move into the less dense layer too. I tried to upscale it with really clean starting material. I think the majority of my first separation composed entirely of water-solubles.

What did you use in the acid-base extraction? NaOH and HCl? Did you measure things out, take note of pH, or refer to better work than mine for required molar math? It is a process that works, and it's efficiency is largely being debated right now. I'm most confident in acid-base extraction or single-solvent, dewaxed hydrocarbon runs with slow evaporation (washes ensuing). Too bad nobody likes sharing information these days.

Correction to last post:
Methanol is not soluble with hexane or heptane but is with water. However I still dont understand what you (Old Gold) did to get three layers of separation.

I took the liberty of visiting the pictures you posed and saw an unlabeled picture with a 1000mL beaker or flask containing equal volumes of a dark black solution and a gold solution. This looks to me like the THCA is in the gold layer and the THC and other trace cannabinoids are in the dark layer. Is this Naphtha and methanol?

Could you post a list of steps or the procedure you used? Even if its eyeballed math it would be greatly appreciated.

Wow! I didn't even know what you were talking about, that picture is an oldie! I honestly don't remember, so let me think on it ... I also left it behind after breaking a separatory funnel (story of my life) and went elsewhere with my work.
It could have been any of three things:
(1) NaOH solution on bottom with potential salts of THCa ... but I am leaning against this because of the likely age of material at the time.
(2) acidic water wash of heptane - leaving cannibanoids in heptane
(3) Saline wash of heptane - cannibanoids in heptane

I lean towards #2 and #3. You're looking at the entirity of the project. First wash. No idea how much starting material. Eyeball the volumes lol

 

[ClandestineChem]

Hope your health/pain gets better! From experience know taring a ligament is very painful.

Quick tip/question before diving into everything:
Do you filter your solution with active charcoal and celite? If not you certainly should. In the lab I calculated almost no loss in charcoal filtration and the solution was significantly better/brighter. Also the extract tastes better as your removing oxidized terps in the filtering process.

Yes I did use NaOH and HCL as my acid and bases. I used rough molar math to estimate the amount of NaOH and assumed that the THCA sodium salt is 1M of THCA and 1M of Na+ (I could be wrong about that). The pH before my digital pH meter broke (mid experiment [murphys law]) of the acid was 2.7 (6 drops of 32% HCl in 1L) and the pH of my base was 12.5 (10g of NaOH per 1L seemed appropriate for the 1-2g of raw BHO extract dissolved in n-hexane). Im not sure if I did something wrong but when the hexane exaporated there was nothing left. I might of been to quick with the procedure as the NaOH water only was stirred with the hexane layer for 5 min tops.

Is there any solvent(s) that recrystallize only THCA and not THC?

Im also still a little lost on your procedure to getting that THCA crystal you took a picture of. After you extracted the oil with acetone and filtered the solution to remove plan material, did you use a NaOH saline solution to turn the THCA into THCA sodium salts? Then did you re-adjust the pH with acidic water to precipitate small THCA crystals? If not please explain.

Your very correct in saying that information is increasing getting less shared and/or free. Thank you for posting those pictures and disusing this with me.

 

[Old Gold]

Hope your health/pain gets better! From experience know taring a ligament is very painful.

Quick tip/question before diving into everything:
Do you filter your solution with active charcoal and celite? If not you certainly should. In the lab I calculated almost no loss in charcoal filtration and the solution was significantly better/brighter. Also the extract tastes better as your removing oxidized terps in the filtering process.

I do this prior to distillations, but haven't really done so otherwise. I've had carbon dust also make it through the initial filtration and somehow the first distillation. It required another filtration over 2.5 micron and a distillation to leave no traces of carbon settling, even when redissolved in alcohol.

Is there any solvent(s) that recrystallize only THCA and not THC?

THCa is significantly more polar than it's decarboxylated counterpart, due to the carboxyl group's electronegativity

Im also still a little lost on your procedure to getting that THCA crystal you took a picture of. After you extracted the oil with acetone and filtered the solution to remove plan material, did you use a NaOH saline solution to turn the THCA into THCA sodium salts? Then did you re-adjust the pH with acidic water to precipitate small THCA crystals? If not please explain.

Your very correct in saying that information is increasing getting less shared and/or free. Thank you for posting those pictures and disusing this with me.

I dissolved winterized oil in naphtha, and washed out impurities with acidic water / denatured alcohol.
No pH readjustment, just an initial pH of 2 or 3 ish or whatever

 

[SkyHighLer]

I do this prior to distillations, but haven't really done so otherwise. I've had carbon dust also make it through the initial filtration and somehow the first distillation. It required another filtration over 2.5 micron and a distillation to leave no traces of carbon settling, even when redissolved in alcohol.


THCa is significantly more polar than it's decarboxylated counterpart, due to the carboxyl group's electronegativity



I dissolved winterized oil in naphtha, and washed out impurities with acidic water / denatured alcohol.
No pH readjustment, just an initial pH of 2 or 3 ish or whatever

"I dissolved winterized oil in naphtha, and washed out impurities with acidic water / denatured alcohol.
No pH readjustment, just an initial pH of 2 or 3 ish or whatever"

Simple enough for a fifth grader.

It's a reversal of the wash described in Cannabis Alchemy with a pH alteration.

Step 6: Purification, Cannabis Alchemy by D Gold,

https://archive.org/stream/CannabisAlchemy/cannabis-alchemy#page/n25/mode/2up

 

[ClandestineChem]

Rely to Sky and Old Gold

Rely to Sky and Old Gold

Skyhighler, thank you for the link. It is a in-depth view of the refining process but not the separation of THC and THCA.

So knowing that THCA is more polar than THC I'm thinking methanol and acidic water should be used as a solvent. (Justification: MeOH also doesn't mix with hexane or heptane unlike EtOH).

While acid is a catalyst to decarbing, the whole procedure will be kept under 40°C (even distilling/evaporating will be done under vacuum) to ensure maximum preservation of THCA.

What ratios of methanol and acidic water should be used? I figure we can't have too much water as it would be a pain to evaporate off compared to any alcohol or non-polar solvents. It's also unfortunate that methanol and water do not form an azeotrope like ethanol and water. The link Sky provided shows equal ratios of alcohol and water.

Is there any chance of THCA going into this acidic polar solution? If not why? If the methanol and acidic water don't dissolve the THCA, then I guess that there wont be any concern about boiling off the water.

Thank you for putting up with my non-stop questions. The reason why I want to be specific is to be able to replicate this process on a large scale. Before I go to my supervisors wanting starting product/oil I need to do repeatable small scale testing.

 

[SkyHighLer]

I have some low Bp pet ether/ethanol/sep funnel at hand, shame on me for not giving it a go.

But I also have ten brands of recently purchased butane awaiting mystery oil test, and some fresh untrammeled Gorilla Glue flower deserving a prompt TLC extraction.

 

[Old Gold]

So knowing that THCA is more polar than THC I'm thinking methanol and acidic water should be used as a solvent. (Justification: MeOH also doesn't mix with hexane or heptane unlike EtOH).

MeOH + H2O is popular as a mobile phase in column chromatography.
Also, for recrystallization purposes, a very nonpolar solvent should dissolve THC before THCa, so washing the crystals pretty should work (probably in cold conditions to minimize subility in general)

I figure we can't have too much water as it would be a pain to evaporate off compared to any alcohol or non-polar solvents.

Thank you for putting up with my non-stop questions. The reason why I want to be specific is to be able to replicate this process on a large scale. Before I go to my supervisors wanting starting product/oil I need to do repeatable small scale testing.

That's why we're here, is it not? I just enjoy sharing my experiences, observation, and research to further the availability of information/education in this world. There is something seriously wrong with education systems in 'murrica.

Best way to deal with heavy water content is under vacuum, with magnetic stirring (or rotary evaporator of course)

I have some low Bp pet ether/ethanol/sep funnel at hand, shame on me for not giving it a go.

How 'bout distilling some denatured alcohol

 

[ClandestineChem]

Crystal attempt 2

Crystal attempt 2

I have about a week left before I have the free time to go back into the lab. Im going to try the heptane and acidic methanol purification and see what it yields. If it looks as good as the yellow crystal old gold created I will attempt to re-crystallize it in a non-polar solvent.

For the non-polar solvent which is better? Chloroform, Diethyl ether, or Dichloromethane?

I have very little experience with Chloroform and I believe DCM is easier to purchase than Diethyl ether. Chloroform being the most non-polar I believe.

 

[ClandestineChem]

Back trying new things

Back trying new things

I finally got back into the lab and was able to try the wet MeOH acidic saline wash. Unfortunately it had very little impact on the end product.

My Procedure was:

1. Dissolved 3.5g of winterized extract in 50mL of n-hexane in a 500mL beaker. Call this non-polar solution.

2. Prepared a 100mL solution containing: 50mL of distilled water with an adjusted pH=3 with HCl , 50mL of MeOH, and 0.9g of NaCl. Call this polar solution.

3. Poured the 100mL of polar solution into the 500mL beaker containing the non-polar solution.

4. Mixed the two layers with a glass stirring rod for 10 minutes.
5. Used a funnel to separate the polar and non-polar solutions.

6. Saved the polar solution

7. Vacuum distilled the non-polar solution to yield 3.4g yellow honey oil.


Observations:
-The polar solution was clear to start. When mixed with the polar solution it turned cloudy.
-The final product was honey oil that was sappy
-(I have pictures I could upload if anyone is interested)

Questions:
-Why did this not work?
-Did I do anything wrong?
-How could I improve?

 

[Old Gold]

I finally got back into the lab and was able to try the wet MeOH acidic saline wash. Unfortunately it had very little impact on the end product.

My Procedure was:

1. Dissolved 3.5g of winterized extract in 50mL of n-hexane in a 500mL beaker. Call this non-polar solution.

2. Prepared a 100mL solution containing: 50mL of distilled water with an adjusted pH=3 with HCl , 50mL of MeOH, and 0.9g of NaCl. Call this polar solution.

3. Poured the 100mL of polar solution into the 500mL beaker containing the non-polar solution.

4. Mixed the two layers with a glass stirring rod for 10 minutes.
5. Used a funnel to separate the polar and non-polar solutions.

6. Saved the polar solution

7. Vacuum distilled the non-polar solution to yield 3.4g yellow honey oil.


Observations:
-The polar solution was clear to start. When mixed with the polar solution it turned cloudy.
-The final product was honey oil that was sappy
-(I have pictures I could upload if anyone is interested)

Questions:
-Why did this not work?
-Did I do anything wrong?
-How could I improve?

It depends on the starting material, and there's a good chance I had some water solubles or chlorophyll in there. I'd be interested in pictures, I was unable to push my experiments further than I did. I've turned similar starting material gold with nothing but water, and sometimes added salt.

I am more confident in prior methods of acid-base extraction, and it is a method that has been proven successful with various carboxylic acids. Maybe the selection of a base wasn't correct, and surely the solvent/reagent ratios were horrible. And maybe someone can further explain how cannibanoids would degrade in contact with hydroxide groups, I don't know. G.O. mentioned that oxides/degradation products of cannibanoids might be soluble in hydroxide solutions, so who knows if hydroxides are catalyzing the oxidation. There is however some potential for too much acid causing a bit of isomerization.

My advice: the fastest and easiest way to great starting material (crystal seeds) is pretty well described in some.of Pangea's posts on slow evaporation. Dewax/winterize it fully prior to this slow evaporation and you'll get crystallization instead of just nucleation.

Hope that helps. Even if trying the acid-base extraction sometime, why not start with pretty clean material?!

https://chem.libretexts.org/Core/Analytical_Chemistry/Lab_Techniques/Acid-Base_Extraction

 

[Old Gold]

My mind is blown that it took this long for even a photo....But.....
alleged CBDa crystals!
https://www.instagram.com/p/BRBZTdGgPHU/

 

[weedaholic721]

Have never had access to to fresh CBDa rich material but was always told that CBDA wouldn't crystallize like d9THC. Always felt that was false.

Awesome post Old Gold

 

[TerpChild]

One of my coworkers at the collective got some 99% cbda crystals at a cannabis cup. They were bright white. I took a 200mg dab and it did not have any considerable effect on my chronic back pain. He paid $100 for the gram. After reading this thread i am wondering if it was cbda or of it was already decarboxylated during their process and they just claimed it was cbda.
One thing i noticed is that the bits that melted to the dabber turned back into exactly the same crystals when they cooled. It was quite different than when you have melted shatter on ur dabber and it never gets back to its original clarity.

 

[Gray Wolf]

My mind is blown that it took this long for even a photo....But.....
alleged CBDa crystals!
https://www.instagram.com/p/BRBZTdGgPHU/

That is about the same color Pharmer Joe's THC-a crystals were, but his CBD-a crystals were white.

 

[SkyHighLer]

G.O. Joe, or maybe GW could inquire of Dr. Kate etc., is there something I'm overlooking when I compare pentane grades and seem to see HPLC grade as actually cleaner for extraction purposes than the other grades?

Specifically, is there anything nasty in the other possible 2%?

General Chemical Specifications for n-Pentane, Reagent Grade (ACS):
Assay (by GC) Min. 98 percent
MAXIMUM LIMITS
Color (APHA) 10
Residue after Evaporation 0.002 percent
Water 0.02 percent
Sulfur Compounds (as S) 0.005 percent

Specifications for n-Pentane, HPLC Grade:
TEST
1. Assay 99% min.
2. UV Absorbance at 190 nm 1.00
3. UV Absorbance at 200 nm 0.30
4. UV Absorbance at 210 nm 0.10
5. UV Absorbance at 250 nm 0.01
6. Residue after evaporation 0.0005%
7. Water 0.01%

Ratings for n-Pentane:
Health: 1
Flammability: 4
Reactivity: 0

Shipping Information for n-Pentane:
Pentane, 3, UN1265, PG II

Storage Information for n-Pentane:
REFRIGERATE: Keep tightly closed.


I'm not linking you to that because they have $168 pending on my PayPal account for a 4L jug delivered to my door.

There are much better deals, that was the first one to ask no questions.


And here's a sample of what to expect otherwise...


New account business form

Tyler Thompson <tthompson@GFSChemicals.com> Today at 11:17 AM
To
'johnxxxxxxxx

Hi John,

Thank you for your interest in GFS chemicals. Before we are able to process your order, we must first have an active chemical purchasing agreement (New Account Form) on file. The form attached is the form you can also find on our website at www.gfschemicals.com under “forms.” Please sign and complete the form in it’s entirety and we will be able to process your order. Thank you again for allowing GFS chemicals serve you.

Thank You,
Tyler Thompson
Customer Service Representative
GFS Chemicals, Inc. Research and Analytical Products Div.
Specialty Chemical Manufacturer, est. 1928

800 Kaderly Dr.
Columbus, OH 43228
(800) 858-9682 x 115
Fax: (740) 881-5989


I'm not Donald John Trump, I don't feel comfortable attesting to, "b) □ I certify that we have professionally staffed laboratories and production facilities with legitimate and lawful uses for chemicals."


III. Explanation of Your Use of our Products: (responses required for all items in III, a & b)

a) □ Laboratory: Analytical/Quality/Research/Development □ Used in a manufacturing process
□ Other: _____________________________ □ Will re-pack and/or re-label GFS product (s)

b) □ I certify that we have professionally staffed laboratories and production facilities with legitimate and lawful uses for chemicals. □ I certify that we will not resell items purchased from GFS with the GFS Chemicals product label affixed thereto.(no distribution) □ I certify that we are US domiciled company and as such will abide by all US Federal laws regarding exports of materials and IP. □ I certify that we are a/an ___________________ domiciled company and as such will abide by all the laws and regulation of this jurisdiction and all UN treaties, trade agreements, embargos and trade restrictions as we may be legally bound to follow.


The astounding hypocrisy is that in comparison I can walk up to the corner service station and score a gallon of gas in a plastic jug for a few dollars no questions asked, or drive off with shopping cart loads of who knows what industrial grade nasties (Coleman fuel and much, much worse) from straight off the shelves of the local hardware store. Besides, I'm pissed, their HPLC grade is only $100 a jug.


It shipped, like I said I used PayPal, one of the simplest, quickest shipping online purchases of anything I've ever made. And they carry other goodies.....

http://www.rightpricechemicals.com/buy-n-pentane-99-online.html

 

[G.O. Joe]

HPLC grade solvents are mostly just used for HPLC and anywhere else the liquid is being analyzed directly. ACS reagent is good enough for any solvent uses. For what the rest may be, first I'd want to go to the library and consult Reagent Chemicals for what may be possible, because no pdf of it can be found. I'd suspect just some closely related alkanes.

High purity n-pentane is not the most widely stocked solvent, but it can likely be found somewhere else. You can't just order chemicals from the major companies without an account. Think smaller, unless you can work something out with a big local solvent supplier, whoever that is there.

 

[SkyHighLer]

Thanks.

P1033-4
Buy Pentane (n-Pentane, 99 percent), Reagent Grade (ACS) - 4L
Each
$176.38

G2491-4
Buy Pentane (n-Pentane), HPLC Grade - 4L
Each
$148.05

P1035-4L
Buy Pentane (n-Pentane), Lab Grade - 4L
Each
$230.13

http://www.rightpricechemicals.com/buy-n-pentane-99-online.html

UPS tracking says it's on it's way up from Texas.

4 x 4L of HPLC grade is only $475.

 

[Gray Wolf]

G.O. Joe, or maybe GW could inquire of Dr. Kate etc., is there something I'm overlooking when I compare pentane grades and seem to see HPLC grade as actually cleaner for extraction purposes than the other grades?

Specifically, is there anything nasty in the other possible 2%?

OK, I sent Dr Kate a query and await her response with bait on my breath.

Looking at it from a practical standpoint, HPLC grades have to be held to a high standard to be consistent and pure enough to use in an HPLC without adding additional peaks besides their own.

As GO Joe notes, the most probable contaminants are higher and lower alkanes.

Pentane is hard enough to keep in the bottle, and the next lower alkane to Pentane is Butane, which is even harder. Ostensibly less of that than longer ones like hexane, heptane, octane, etc.

Reagent grades for pharma or food preparation is ostensibly more tolerant of contamination by other alkanes, because the alkanes are relatively non toxic.

Some concern with hexane and heptane, because our livers turn them into a 2.5 Dione, which is a carcinogen.

On the other hand, the FDA lists both pentane and heptane as Class III, and only hexane as Class II.

I would personally pick pentane and that is what we mostly use these days instead of hexane.

 

[SkyHighLer]

Thanks, in the mean time.... back to the chase.

I was checking out the pricing and availability at eBay, and noticed an offsite listing that sounded familiar, Gas Innovations.

http://gasinnovations.com/literature/nPentane.pdf

The source of BVV and RHS's superb USA butane and propane.

Give it a thought Adam.