Does anyone have any idea what would cause heptanes and 100% MeOH to become miscible? I was under the impression that they would be immiscible at any ratio, and they certainly are when poured virgin from the barrel.
I just lost a bunch of MeOH in some heptane micelle. 600ml of virgin MeOH in 1500ml of heptane/oil solution and couldn’t see any separation anywhere. Scooped a little off the top and added some virgin MeOH and it mixed right in. Added 5% water, mixed right in. Added 10% water and a quick stir, now my layer comes back. Why do I need to louche my alcohol from what is supposed to be an immiscible alkane?
I guess I’ve never seen an emulsion that looks this homogeneous with no film of top layer or bottom layer before (at least not without intentionally homogenizing/dispersing). It’s pretty dark but there’s no structure in the fluid that I can tell and the turbidity doesn’t seem that high. I suppose that’s a reasonable explanation though
I will try to scare some up. I wish I had taken a video when I first added the water, it looks cool as shit because it stirs in for a while before it finally kicks out a biphasic layer
So, it seems that pure methanol will hold approx. 7% Heptane by weight. Adding 5% water does not kick out an appreciable amount of that even when left overnight. Adding 10% causes it to separate in about 5 minutes when there’s nothing else in it and around 10 for our extraction micelle.
Interesting note about solvent recovery: the MeOH/C7 azeotrope causes you to leave any water in the rotovap ball if you distill the fractions together (ie they weren’t separated perfectly) this will give the impression that there is little to no heptane being recovered until you add water back in.
Since room temp heptane extractions yield relatively high quality extracts aside from the high fat content, so a LLE to methanol leaves behind a VAST majority of the fats while pulling the Cannabinoids after a number of methanol washes. I believe there is a more efficient way of doing this at an industrial scale due to the number of washes to get all your goodies and the time it takes for the two layers to separate.
If you extract in methanol, going to heptane will kick out all the sugars. If you extract in heptane, going to methanol will kick out a lot of the fats. So there are some benefits in either case.
Yes yes and yes lol. We didn’t extract with heptane but as @MagisterChemist said, there are benefits for going either direction. We have some really nasty material and most other methods of cleanup induce a lot of loss. Going from MeOH to heptane is a real pain because the partition is poor but going the other way is a breeze and quite low loss. Mostly we’re just fooling around though TBH.
For sure it’s super easy to push them over by adding more water but I like keeping the methanol at the same proof as we use for other things (that is, not 40% water).
Honestly it seems much less resource intensive to reproof by leaving approx 50% Heptane with the deproofed methanol and distill via rotovap than deal with the sieves. It’s just a lot of shit to bake at any kind of volume. Despite their close boiling points, we actually have had pretty good luck distilling MeOH directly (obviously not hitting 100%). All said though, reproofing is another step and one the bosses don’t like to see because it means there isn’t any oil in the equipment while we are doing it.