How to isolate and purify THC, CBD, CBN

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There are other ways to isolate these compounds (phase transfer catalysts), but an even better option is column chromatography.

But first, a word about decarboxylation. Whether to decarb can be debated forever, but if you do, it should be heated under nitrogen at 105C for 1 hour.

I like to use a non-polar solvent to extract and a polar solvent to wash. Besides butane, try propane, hexane, and chloroform (especially efficient). Absolute ethanol (200 proof) is my polar solvent of choice.

When you intend to isolate the individual cannabinoids you should stabilize the crude product. With the product dissolved in 100% EtOH before winterization, filter the solution through charcoal, extract with 2% sodium sulfate, then filter through charcoal again. This prevents oxidation of your crude product.

The odoriferous terpenes can be removed by steam or vacuum distillation. Cautious distillation in vacuo yields a fraction of crude red oil (bp 100-220° C/3 mm). This can be purified by redistillation or column chromatography. Use ethanol to remove the residue from the flask while it is still hot. Filter the solution through charcoal, and strip the solvent. Distill the residue to yield pure red oil (bp 175-195° C /2 mm). Distillation must be stopped if smoke appears, indicating decomposition.

Because THC is heat-sensitive, it is preferable to isolate the cannabinoids by column chromatography. The simplest method of column chromatography is performed with ethanol and ether extracts of hemp on alumina, yielding two major fractions: (1) chlorophyll, CBD, and CBN, and (2) THC. A second, more difficult method is performed on Florisil (use 10 times the weight of the oil) with the solvent system hexane:2% methanol. This yields a doubly-concentrated, viscous oil which can be repeatedly chromatographed on alumina to separate the THC and CBD. The CBD fraction of column chromatography can be distilled (bp 187-190° C/2 mm; pale yellow resin) to purify it.
i was just reading on sigma aldrich about the use of chloroform for extraction, and fractional distillations.i think ill stick to the distilling our own n butanes and using rosseville ethyl 200.

you following the limonene extractions?
 
Here is a demonstration of producing nearly pure thc from an extract.

This ia a chromatography run that demonstrates a much less than perfect setup that produced the fraction shown in the youtube thumbnail for the video. Vaping this pale yellow and sticky substance confirms it is nearly pure thc. Until you do your own chromatography you will not realize how much chlorophyll there is! The green fraction in the video when purged of solvent is a black tar that smells nasty.

This run demonstrated that I need to pack the column tighter, however it is a Dry Column Vacuum Chromatography (DCVC) mode and banding does not present a real problem because the solvent gradient is continuous and thr columns are sucked dry.

This is precisely how to purify an extraction into nearly pure thc if you are on a budget. The second video is the "go to" video if you want yo learn how to do this. It was the second video that showed me how to start doing this and full credit to those guys!



https://www.youtube.com/watch?v=6A6CXRbKJeA
http://curlyarrow.blogspot.com/2017/02/dry-column-vacuum-chromatography-dcvc.html

View attachment IMG_0121.jpg
 
There are other ways to isolate these compounds (phase transfer catalysts), but an even better option is column chromatography.

But first, a word about decarboxylation. Whether to decarb can be debated forever, but if you do, it should be heated under nitrogen at 105C for 1 hour.

I like to use a non-polar solvent to extract and a polar solvent to wash. Besides butane, try propane, hexane, and chloroform (especially efficient). Absolute ethanol (200 proof) is my polar solvent of choice.

When you intend to isolate the individual cannabinoids you should stabilize the crude product. With the product dissolved in 100% EtOH before winterization, filter the solution through charcoal, extract with 2% sodium sulfate, then filter through charcoal again. This prevents oxidation of your crude product.

The odoriferous terpenes can be removed by steam or vacuum distillation. Cautious distillation in vacuo yields a fraction of crude red oil (bp 100-220° C/3 mm). This can be purified by redistillation or column chromatography. Use ethanol to remove the residue from the flask while it is still hot. Filter the solution through charcoal, and strip the solvent. Distill the residue to yield pure red oil (bp 175-195° C /2 mm). Distillation must be stopped if smoke appears, indicating decomposition.

Because THC is heat-sensitive, it is preferable to isolate the cannabinoids by column chromatography. The simplest method of column chromatography is performed with ethanol and ether extracts of hemp on alumina, yielding two major fractions: (1) chlorophyll, CBD, and CBN, and (2) THC. A second, more difficult method is performed on Florisil (use 10 times the weight of the oil) with the solvent system hexane:2% methanol. This yields a doubly-concentrated, viscous oil which can be repeatedly chromatographed on alumina to separate the THC and CBD. The CBD fraction of column chromatography can be distilled (bp 187-190° C/2 mm; pale yellow resin) to purify it.

Here is one of my chromatography runs done in preparation for molecular distillation using a modified kugelrohr concept. Then I post the tech video to set up for molecular distillation. Finally time lapse of the distillation proceeding. If you look close at the time lapse you will see that the boiling flask bumped some contaminate into the collection bulb. This happens often on the first pass. I place the collected bulb into a new boiling flask and use a hand torch to heat the extract and thusly transfer it into the new boiling flask. This avoids passing any extract across a vacuum grease joint. .then I run it through again then sometimes again. Each run through the rig progressively refines the extract closer to absolute. These are gram sized quantities.

Semper Fi

https://www.youtube.com/watch?v=BIsiCfcLBL4
https://www.youtube.com/watch?v=D-A-ZsU8ZxQ
https://www.youtube.com/watch?v=uBpuKVaXynE
 

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