We recently replaced the subcritical extraction of n-butane with a CO2 system.
Everything went quite well until crystallization, where I found that the crystals did not form well and the mixture looks like porridge.
The only difference I noticed was in the distillation, when the body, instead of being yellow as always, became reddish.
I processed the same biomass as with butane and I kept the same parameters from winterization to crystallization. Initially , I thought something had happened because I extracted from non-decarb biomass, but I had the same problem when I used decarb biomass.
I really can’t figure out what the problem is and I’m curious to know if anyone has faced anything similar so far.
I apologize for my English, but it’s not my strong point.
Could you provide a little more info? Is this CBD biomass? I assume so because it is crystallizing even though you said it was distilled (and therefore decarboxylated). What steps do you take from start to finish? It’s also not quite clear - are you doing butane extraction now, or CO2 extraction now? What solvent are you crystallizing from?
First thing I would try is a methanol test. Co2 is notorious for pulling large amounts of fats and lipids. Take a gram of your oil dissolve it in some methanol 10:1 should be fine and freeze it. See if any lipids jump out at you. I’m guessing you’re seeing more fats than you are used to with butane.
Now I run only with CO2 system and hemp biomass ( 3% and 5 % CBD) . The biomass is grinded at + 80 mesh , well dried and decarbed at 140 C . Extraction time 90 min , Extraction Vessel 20Mpa/55 C , 8 Mpa /40C Separator 1 and 5Mpa /25C separator 2 ,flow 100L/h .
Then winterization and filtration ( medium and slow ) until no waxes , rotovap , distillation ( 1 pass ) and crystallization with n-pentane 2:1 w/w distillate/pentane (seeding with 1 % of CBD crystals) , freezer at -25C for 3-4 days .
At first I also tried non-decarb biomass and I used ethanol as a co-solvent…and it was a mess.
In the last 2 years I have made more than a hundred batches of isolate, from distillate obtained with butane and everything was perfect.
Thanks, I will try …its true …I pull a lot of waxes and the filtration its a pain .Usually I make 3-4 filtration until I see no waxes after 24 h from the last one .
When it comes to co2 I’ve had good success doing a room temperature (21c) pre filtration at about 25 microns. This seems to immediately remove about half the fat load. The more polar the solvent you choose the better this tends to work, methanol being ideal. Then we freeze at -50c for 24 hours and run through a 1 micron filter. We’ve definitely seen adverse reactions when it comes to making isolations with fats/lipids present. Best of luck!!!
I also tried at room temp through 2 coffee filters , then -25 C for 24h , then 11 microns filter ,another 24 h ,and then 2 microns filter . I also thought that can be some lipids ,waxes or gums in distillate because after I pour some cold pentane , mixed and crushed the crystals, when I tried to filtrate the ML the result was something like this …a paste mixed with crystals…
Its light because I washed with pentane and I didn’t use any media powder …so probably I still have fats/lipids in distillate .
My main concern is that in about 2 weeks I will have my flash chromatography in my lab and I still don’t know if these compounds that I have in crude will cause me problems. I also want to change my procedure… winterization ,colour remediation and then directly to the flash.
That methanol test i mentioned will confirm wether or not you’re dealing with lipids. By far the simplest way to test it. IMO impossible to tell from the picture. Looks like a slurry of isolate.
As long as your prep is proper you shouldn’t have any issues. Using a .22 micron syringe filter is quite common as the last step in HPLC prep. Even if lipids make it through it’ll just wear out your column/media a bit more quickly.
Flash chromatography as your last step is going to be very expensive and challenging to scale up. Looks like you’re making several hundred grams at a time - this will be an intense amount of solvent, silica, and time to purify all of it. I would continue to try to figure out your crystallization…
Decarb biomass → extract with CO2, initial filter → winterize and filter as cold as possible. If there are still waxes and fats in the extract, reduce the amount of ethanol in your winterization (e.g if you start at 10:1 ethanol:extract, reduce that to 6:1) and refreeze. Filter again → Distill (if necessary) → crystallize in pentane. In my experience you can use a lot more pentane than you mentioned. Try 3:1 pentane:distillate or even higher than that instead of 1:2 pentane:distillate. This should help keep your lipids and gums in solution while CBD crashes out.
In terms of the biproducts causing problems on your column, you should be OK if you don’t overload the silica. The remaining non-polar waxes after winterization will elute very fast. Gums are a bit more polar so they might be harder to remediate. Good luck
Dissolve your crude in methanol 10:1 meoh:crude to winterize. After you filter it wash your methanol with heptane till the heptane comes out clear. The heptane will pull the cannabinoids from the methanol while the non polar chloraphyll mostly stays in the methanol. I do not recommend using any water as any polar solvent holds a few ppms of water and from my experience that water will have red chloraphyll in it
.Usually I make 3-4 filtration until I see no waxes after 24 h from the last one .
