Thank you for replying.
What type of chromatography would be appropriate?
I actually started another threading specifically on chromatography.
Many thanks in advance for your guidance.
Chromatography may not be your only solution. Crash out isolate, formulate with your mother liquor. You won’t achieve very low cbd concentrations but you could swing things favorably in that direction
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so what is in your extract now?
a “THC-rich extract” requires THC in the starting material. same for CBD. I’ve run into quite a number of folks that don’t get that, and want “just the CBD’s” out of the White Widow, so their RSO doesn’t get them high. it can technically be done, but it makes zero sense to do it.
most “hemp” (drug strain cannabis bred to produce CBD) produces about 30:1 CBD:THC, most drug strain cannabis are better than 100:1 THC:CBD. so just extracting the right input is a whole lot easier than trying to get a “high CBD” or “full spectrum” and a “high THC” fraction from the same starting material.
if you’re starting with a high CBD extract, decarb, and possibly distill. then crystallize the CBD. the bit that doesn’t crystallize will be enriched for THC and all the other non-CBD bits in your starting material
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Sorry, what do you mean by “Crash out isolate, formulate with your mother liquor”?
English is not my mother tongue. I may not fully understand slang phrasings.
Thank you for reply in any case.
The starting material is a high CBD extract, depending on the strain, and growing conditions, ratio is 1:25 to 1:40. Unfortunately, where I live, THC dominant strains are illegal. By “THC-rich full spectrum extract”, I was meaning CBD-poor extract (hence the brackets).
Blockquote
if you’re starting with a high CBD extract, decarb, and possibly distill. then crystallize the CBD. the bit that doesn’t crystallize will be enriched for THC and all the other non-CBD bits in your starting material
Yes, that is somehow may starting idea. How does one crystallize the CBD only? I am not sure to understand this separation step.
Thank you for your guidance.
My apologies,
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Thank you!
I like the well temperature swing crystallization method. It probably preserves better the phytocompounds than heating.
Just out of curiosity. How many people have tried/used that procedure, and what is the purity of the CBD isolate? I am wondering how specific to CBD is the crystallization. What other cannabinoids are crystallized along with CBD? So many newbie questions that betray the ignorance of the person.
Many thanks.
As far as co crystallization the only other cannabinoid I have personally seen in isolate samples is CBDv
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Noted. Thank you.
Hexane is not unharmful, though…
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That’s how crystallization (usually) works. You only get a crystal if all (most of) the molecules are identical…
Crystallize 3x and you can be above 99% purity.
https://www.google.com/search?q=purification+by+recrystallization
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After re-reading the procedure given earlier, I realize that their starting material is a nearly-pure-CBD extract.
In my case, I meant to start from a full spectrum extract. My question was pertaining to collecting CBD isolates on one side, and still preserving the rest of the extract on the other side. Are cannabinoids so different in terms of solubility that they can be separated by recrystallization? Or, have I misunderstood the procedure, or the comments, or both? Now I am confused.
Many thanks for any educated guidance.
Cbd is relatively easy to crystallize from impure solutions
Any cbd content higher than 65% will crystallize simply via sitting long enough
Side note: What’s your native language?
Man thanks for replying.
Are you positive about separating CBD from the rest of the extract (preserving both the CBD isolate and the rest of the extract) by crystallization? This is confusing to me.
Still very open for any educated information. Thanks.
Side note: perhaps French. Is my English that bad?
The cbd will crystallize,
The rest of the extract will remain a viscous liquid oil
You will need to dissolve the material in an alkane
Heptane is a good choice as it has a high boiling point so it will reach super-saturation slowly
Measure the materials volume
Measure twice that volume of heptane example: 1000ml distilled cannabinoid extract
2000ml heptane
Bring the material to 94c
Bring heptane to 94c
Add heptane to extract under heavy stirring
Mix thoroughly
Let solution cool to 30c, slowly, do not accelerate cooling process
Drop temperature of solution to 25c, slowly-
apply strong mixing
Drop temperature to 20c, slowly
Apply strong mixing
Drop temperature to 15c slowly
Apply strong mixing
Drop temperature to 10c slowly
Apply strong mixing
Raise temperature to 15c, slowly
Apply strong mixing
Drop temperature to 10c, slowly
Apply strong mixing
Raise temperature to 15c, slowly
Apply strong mixing
Drop temperature to 10c, slowly
Apply strong mixing
Drop temperature to 5c slowly
Apply strong mixing
Raise temperature to 10c slowly
Apply strong mixing
Drop temperature to 5c slowly
Apply strong mixing
Raise temperature to 10c slowly
Apply strong mixing
Drop temperature to 5c slowly
Apply strong mixing
Raise temperature to 10c slowly
Apply strong mixing
Drop temperature to 5c slowly
Apply strong mixing
Raise temperature to 10c slowly
Apply strong mixing
Drop temperature to 5c slowly
Apply strong mixing
If you extract has fats or waxes due to insufficient winterization or lack of water-washing, they will begin to fall out of solution near 0c and solidify
This will ruin your yield, by coating the crystals in a shell of wax and inhibiting further crystal lattice formation
If your extract was de-waxed and washed with water, you may proceed to drop temperature to 0c and mix again, and cycle in this fashion down to -5c and then down to-10c
If not, do not go lower than 5c
Continue cycling temperature up and down in this fashion until all no more crystals form.
There is no need to drop temperature past -10c
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Thank you replying.
I am not sure to understand the “Bring heptane to 100c”.
100°C or 100F?
Is it suppose to be done in a pressure vessel under inert gas? It seems extremely harzardous. 
Still confused…
Sorry I mixed up my BPs
Bring it to just under boiling
94c is fine
Your English isn’t bad, either- I was just curious.
If I know that my writing is being read by a non-English speaker I modify the way I write to ensure clarity
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The problem with rowans method is the ability to purge heptane from the terp fraction.
Butane or bust famalam
If not heptane, then hexane as was suggested earlier?
After crystallization - then evaporation of the solvent, how do you make sure that it is really gone? What is the usual amount of residual solvent in the solute (@ what T, t, P evap)?
Many thanks for your comments so far.
If you go with heptane you can’t purge the mother liquor without destroying the terpenes. Its not likely you have any good terps in there anyway