fraction distillation

distillation
#1

Hi everyone, I hijacked a thread earlier so i figured i would post a new thread. I did 1st and 2nd run on a cheap china 5L. I couldn’t get my vacuum even close to where i wanted. But i did get a descent oil. a few questions. Im trying to fraction off THC from my CBD. I attached some data and pictures of oil. Is my problem with my HPLC results that i didn’t have enough vacuum? I was expecting to see a high CBD low THC. I ran my Mantle 1 degree after 210C

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#2

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#3

The boiling points of thc and CBD are very similar. There’s pretty much no way to separate them via distillation.

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#4

I kind of thought so then someone said you could, maybe in theory but i couldn’t get it to happen. So flash chromo?

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#5

It’s technically feasible, but largely impractical compared to chromatography.

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#6

You won’t get there with a short path. As tweedledew states, it is possible if you have enough theoretical plates and in the petroleum industry tight fractioning is done all the time. However, those systems are large industrial-sized fractioning columns 2-3 stories tall which provide the requisite number of theoretical plates to get the job done. That’s not to say we can’t get there someday with something like a spinning band column but we aren’t there right now. Neither short path nor wiped film will get you there because as tweedledew noted, the boiling points are very close together. This can be further complicated if the crude isn’t pre-processed properly which causes heavy tars and particulate matter to hold on to cannabinoids longer past their normal boiling points.

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#7

I believe it’s actually worse than that…

My reading says that as you bring the vac levels down, the boiling points get MORE similar, as they are now predominantly based on MW.

With THC & CBD being isomers (same MW), sucking harder actually makes the problem of separating them more difficult.

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#8

Yeah could be, that would make for a very interesting research paper!

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#9

Hot condenser tek works mildly, I can get down to 1.5% with short path, but sacrificing CBD potency, then LLE after that to get it down further. Still not practical, but if you just need to get it down enough to not cut carts down significantly it does work.

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#10

@OBXtracts What tek are you using for LLE and how have your results been (assuming you’re talking about remediating THC with LLE)?

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#11

Hexane/brine wash. Results have been less than stellar, but we’re kind of flying blind as people are still hush hush on the methods as it’s new. We’re still nailing down the process and almost to the point where I might just give up and get a chroma column. If I’m getting ~1.5% with short path on a single run, we’re beginning to play with the idea of using that tek for first pass and up to 3 to see what we can get it down to.

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#12

I wonder if a spinning band is capable of separation of this fraction?

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#13

@OBXtracts That’s interesting. With each rinse what change in cannabinoids are you seeing? Do you lose a lot of CBD with each pass? Thanks!

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