Alex: interesting.( a credit to you!) I am curious as to what you actually think the product
is. That is to say the state of the carboxylic acid (ionized or not)
in the crystal. If ionized, it must have a counterion…or perhaps an ion pair of THCA
is crystallizing…it would be most interesting to see an ICP-MS of one of those crystals.
It would answer a lot of questions for the curious. If it is simply non-ioned H+ form crystalizing, is the water suppling the H+ and turns slightly basic?
if you run a similar volume of THCA hexane solution in a parallel jar with out
water…do you get the same phenomena? i.e., a control without water interface.
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Slow growth of mono crystals is observable without water but they’ll generally grow into the side of a dish as they’re growing and end up imperfect. Some people have really solid ways to avoid that
I hadn’t thought about the THCa being seeded by or growing with deprotonated THCa. I don’t think that’s happening because so little would be in the water when compared to the heptane
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I was thinking more of an interface structure with COO-- sticking into
water,a specialized monolayer induced by water, setting up a crystallization platform in hexane side…? or in similar configuration, pair bonding with the submicromolar Ca++
leaching from glass…wild stuff! Does the water interface act as a “crystallization catalyst”?
Yes, the sidewall phenomenon, is simply another interfacial surface. …
Can you substitue a teflon flask for glass?
Thanks in advance, and a very nice piece of work.
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May I ask why your solvent of choice was heptane instead of pentane?
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Heptane is easier to deal with in a laboratory environment at around 70-90f.
What we would normally do is suspend the oil in an ideal amount of heptane. Some amount where very little THCa will want to hang around in it but there will still be a nice mother liquor of heptane for the pigments to trap into
On top of that heptane solution you can add pentane and then allow it to evaporate slowly
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You can also add other solvents to the mixture to effect the crystal shape. I would probably seed using crystals grown in a pentane mixture with ethanol
Step 1:
Use a mixture of heptane pentane with a cosolvent that encourages THCa to grow as needles and with longer terminations
Step 2:
Seed a mixture of heptane and pentane with the seeds from step 1. Grow big clear diamond shapes that aren’t just the normal heptane blocks
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I’ve been enjoying the growth of the thread! I thought I’d share a quick video of some work using this tech and big thanks to Alex Siegel for sharing all the information here for us all👍
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Just had a thought
What if we threw a sonicator at this? Or at least into the alkane portion. I’d think some agitation might get these stones to drop faster.
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I have a pentane / ethanol jar going. I’m thinking of adding it to a flask with stir bar and a dry ice cold trap and regulating vacuum to slowly saturate the mixture while keeping the solution cold
Sounds good. All of my experiments have been done at essentially room temp using warm heptane to super saturate
At the moment I’d recommend using only a few percentages of ethanol maybe 10% maximum
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10% ethanol to water correct?
10% ethanol 90% heptane. I would do this to grow seeds and then make them bigger in a heptane mixture later
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Clearly the pentane or heptane saturates with water over a weeks time course.
You mention adding EtOH to pentane 10% to enhance needle like crystals…
some sort of antisolvent?
Have you tried saturating the alkane with water first…then layer that on water?
Or are we talking layering MgSO4/Na2SO4 “dried” solvent-solution layered on water.
When THCA drops out of terp laden sauce…that is an incredibly impure solution…
so ther must be something catalyzing the crystallization step…
Here you stress “it works best for pre-purified THCA” …any thoughts about this?
but I see photos of crystalline material that looks like the Na+COO-R salt form as well.
any comments? No one seems to point out these obvious two types of preparations.
Have you ever done a LLE of the pentane solution with distilled water, let it settle
and measure the pH of the water phase?
Ion pair extraction of carboxylic acids (ionized state) paired with counter ions into
hexane (alkane solvents) is a well known phenomena. Ion-Pair Solvent Extraction of EDTA Anions with Tetraalkylammonium Ions in Various Organic Solvents | SpringerLink
So when people say they extract with butane…I am not sure what it is they are extracting
becasue no one knows the state of the of the THCA in the Trichome vacuole.
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We’ve done a trial where after setup (THCa, heptane, pentane layer on top of a water layer) then shake. Shaking mixes the two together and seemed to leave some water in the top layer. It was cloudier than normal but mono crystals formed in that solution better than any other, now that I think about it.
So those of you doing this in mason jars and also have a way to remove the water from mother liquor later, maybe try shaking the mixture before letting it sit. I would not try this with ethanol in the mixture because you’ll probably lose some of your alcohol to the water layer
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Crystallizing with terpenes and other impurities is more difficult. Slower and lower yields so I would recommend doing this as a recrystallization of already crystallized THCa or use very pure crude that was going to crystallize on its own
I think the crystal shape here is more about the geometry of the surface it’s growing on, nothing more. Are you suggesting that the THCa could be entering the water layer then recrystallizing at the interface? I think it’s far more likely we’re just seeing a physical effect nothing chemically changes
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If you can share a photo of the types of salt THCa crystals you’re talking about that would be helpful.
And if I can be proven wrong about there being no chemical changes, that would be very cool!
How would we go about doing an experiment to test if the seeds are a THCa-salt?
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AlexSiegel: Your work is thought inspiring! In no way am I trying to “prove you wrong.”
I am trying to promote general thought concerning alkane solutions of carboxylic cannabinoids and butane extractions of carboxylic cannabinoids. US20150038567A1 - Cannabinoid Carboxylic Acids, Salts of Cannabinoid Carboxylic Acids, and the Production and Uses of Same - Google Patents
Please take note of this patent which lays the ground work for my thoughts…
that and an understanding of pK values and ionization in “aqueous solutions”
(Ion-Pair Solvent Extraction of EDTA Anions with Tetraalkylammonium Ions in Various Organic Solvents | SpringerLink)
The later explains the ion pair extraction into Hexane as example.
When one has a BHO “extract” derived from plant material…
how do you know whether you have ion pairs dissolved or whether
you have the non ionized Hydrogen form dissolve, or a mixture of both?
So it is an "a prior " question.
The THCA synthase is excreted into the extracelluar lumen…that means CBGA is also
excreted. The synthase likes to work in aqueous environment at pH 5.0.
At this pH the cannabinoic acids are 99:1 ionized. So I would "assume ’ the speicies loaded into the catalytic cleft is ionized. Since the surrounding milieu is probably a monoterpene
solution of hydroxlyated terpenes acting somewhat as a detergent in some-sort of “aqueous
environment” I would expect Na+and Ca++ ions everywhere. In fact, Ca++ is known to be pumped into plant vacuoles. I do not know how butane solubilizes
THCA or what form THCA is in , in the trichrome. (read the above papers for reference)
Your post is most interesting because it brings the Cannabinoid Alkane Solution/Extract into direct contact with water!
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Example:
In their patent on CBDA methyl ester, Mechoulam et al. synthesize CBDA as a precursor to the methyl ester step. CBDA synthesis below:
Synthesis of Cannabidiolic Acid (CBDA):
A mixture of Cannabidiol (CBD, 314 mg, 1 mmol) and 2 molar solution of Magnesium Methyl Carbonate (MMC/2M, 1.5 ml, 3 mmol) in dimethylformamide (DMF) is heated at 130° C. for 3 hours. Then the reaction is cooled to 0° C., acidified with 10% hydrochloric acid and extracted with ether. The organic layer is washed with saline, dried over the drying agent magnesium sulfate (MgSO4) and then evaporated. The crude compound is then cleaned by column chromatography (20% ether-petroleum ether)."
In regards to this posting, look closely at the 1.) acidification step prior to extraction in to ether. They are using 10% HCl which is pH= -0.5. (minus emphasis)
If you want the carboxylic acid in H+ form…this is how you do it.
2.)Then in a second step they back wash the ether with sat’d NaCl before evaporation.
second step confuses me a bit, but it is possible that it is an ion exchage step.
I’m trying to look as this ??? on going.
Comments?
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Edit. Misread
Love it! Always want to play whit water. I want to try this water layer tek with my diethyl refined crude mixture, the dieth carryer a lot of water…and they act as a antisolvent. Before i dry the solution sometimes is very cloudy.
When the solution is very wet, aprox 70%crude 30% solvent, if i seed in this moment start crystalization in the moment.
Sooo lets do some test.
Thanks
Regards!
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