I’m currently running a procedure where I’m washing my heptane with methanol. Then popping that cannabinoid laden methanol into my membrane skid.
I’ve been using a conical vessel to achieve separation, but noticing a thin film of heptane still making it through and resting in my membrane reservoir that’s supposed to be purely methanol.
Normally I wouldn’t be worried about it, it’s maybe 200ml over 50-60L , but it’s getting whipped around by my pump, and inevitably some heptane gets mixed into the flow and is passing through the pump. This becomes a problem as the diaphragms/seals aren’t compatible.
I’m curious if there’s a column or something I could run things over to achieve a finer degree of separation. Or if anyone’s got some hot tips.
I don’t wanna blow out my hydracell for obvious reasons.
It’s unwinterized. Extracting with 5-10c heptane (room temperature in a cold room).
Figured the heptane would hang nicely into the fats and the methanol would pull the cannabinoids.
I’ve also got a winterizing & color remediation membrane for the methanol later down in the process to take care of any contaminants.
I’m taking bits of fat laden heptane at a time and evapping to clean it up and throwing back into the extraction to prevent fat accumulation. Ideally I’d just use another dewaxing membrane on the heptane but it’s extra $$ that I don’t have.
if you do a LLE of pure methanol a heptane in a separatory funnel.
Shake 50 to 100 times…let it sit 15 min or so …What do you have?
You have a two phase equilibrium mixture …that is to say…
you have heptane saturated with methanol solution layered over the top methanol saturated with heptane…the Kd for each. The Kd are temperature sensitive, and may favor less methanol in heptane at lower temps as Siegel suggests…but you are never going to get all the heptane out. at 20 C you will have 25 gm heptane per 100 ml methanol.
So if your membrane separation works…with this amount of heptane saturated methanol…just wash the membrane at the end with methanol.
and switch seals in your diaphram pump…or move to a PTFE sealed pump.
???
Otherwise, if you must…rotovap it and redisolve in pure methanol…
Silly me, I forgot immiscible just means hardly misicble
If I run it through my membrane and concentrate it (with better seals) is there a way (without evaporation) to remove the heptane?
Will a small amount of water force the heptane out more? Or is the perhaps some kind of silica/column that will drag the heptane while the methanol and cannabinoids flow through?
My last step after concentration is actually louching into pentane to make sure my Terps stay intact. Pentane makes a poor extraction solvent so I wasn’t going to use it in the first step; and I’m worried that trace heptane is going to stay in the mixture after the pentane is evapped, effectively undoing my efforts to conserve the low boiling Terps.
Freeze and decant sound like the best option. But wondering if we got anything else!
Yeah, but I can’t do 100lbs an hour with butane on a budget (sub 10k). Plus it’s much more volatile (gotta keep the monkeys safe), and I’ve already bought these nice shiny membranes. And heptane/methanol are relatively cheap
Oh, just as a note, I’m only doing the heptane on live material. I just use methanol as then initial solvent on dried material. So it’s not a huge issue unless I’m doing fresh.
Clearly you have a bit of water anyways…
no harm in prepping up a serial dilution of methanol/H20 mixtures,
5-30% to see what will work before some sort of precipitation or micelles set in. Do it quick as LLE in test tubes…it might help…and a little extra water should be no problem with the membrane…a little …as things can obviouly get gooey fast.
