This month I ran a counter current seperation process that for a first time seemed to work well. It is useful if you want chromatography type results but without the gel and columns and such. You must use a set of solvents that are immiscible in each other and hexane is immiscible in methanol and water. Methanol and water are miscible in each other in all proportions. So a methanol/water layer will not mix with hexane and will form a layer under it. The idea is that at some ratio of methanol to water that some compounds will have a greater affinity for the methanol mix than the hexane and will go with the methanol mix out of the hexane layer.
I first dissolved the extract in 100 ml hexane. This went into the 500 ml seperatory funnel and represents the stationary phase. Black gunk will get left behind in the hexane and the cannabinoids will wash out of the hexane.
I mixed water in methanol starting at 90% water to 10% methanol. I poured this through the hexane and mixed back and forth gently then allowed layers to seperate. Then I drained off the bottom layer which was cloudy a bit. I then added 10% more methanol to each successive 100 ml pour through of the hexane gathering more terps and such from the hexane layer as the methanol/water washed through. At 60% methanol to water the methanol layer when settled had grabbed significant compound but not yet cannabinoid. This was put into my gunk beaker, along with the black hexane layer later. (I eventually do a gunk run on all my tail ends and often glean good amounts THC but it takes high temp runs to do and is tedious)
I kept ramping up the methanol and found that 97% methanol to 3% water was the ratio that grabbed all the cannabinoid from the hexane, leaving a black mix of who knows what behind in the hexane and the red brown color band holding the cannabinoids are carried out of the hexane with the methanol water mix at that ratio.
The cannabinoid seperation doing this is pretty darn good but not as good compared to my DCVC column but it is cool to watch and simple. The bonus is no lost product and not that much solvent. Next time I would go from 60% methanol to water mix to the next 100 ml at 97% methanol/3% water instead of steps. It should grab all of what I am wanting in one wash and I discard the gunk it grabs out at 60% methanol/water and keep the 97% mix with the cannabinoid profile in it.
It is not as good as a Chromatography column but there is no packing it either. I thought I would pass it along. I am sure the solvent system could be tweaked for more precise results. Thoughts?
Yes I have tried that but not with Ph modifiers. I found that salt crystals would form in my extract after that lolz but no big deal. I tried a number of variations on the theme too but did not pursue it further.
This is room temp iso extract on the left, ending in a Heptane solution on the right.
The THCa was partitioned several times, but the most effective separation was after the initial Heptane extraction from the iso. The THCa was then extracted from the Heptane with pH 14 saline. Heptane discarded, then the THCa crashed out of the saline with pH 2 saline. THCa then recovered with fresh Heptane.
This pH swung saline separation was extremely effective.
As for salt remaining in the extract, while in a nonpolar solvent, be sure to fully extract residual salt with your polar solvent. H20 being the cheapest option
Question on this…where you state “the most effective separation was after the initial Heptane extraction from the iso,” does this imply a heptane extraction of the iso solution, or was the iso removed to a residue first?
@Beaker how are You
Hope that your medical isseus are at a draw for the leasf
No News good. News i hope.
I want to try your hexane / methanol3%water wash to see wat non polar scum can be removed
What ratio of crude to methanol water was used ?
Ratio of hexane to methanol water crude was used ?
Would a iso water 70/30 wash be advised after ? The boil teck ?
Thx in advanced Rogue
I use a 500 ml sep funnel and fill approx 100 ml hexane. Methanol additions are about 50-100 ml. I always start at about an ounce. I do not know what the optimum ratios would be but this works at my scale.
The water gets added to the top of the sep funnel and seperates. Adding more water then drives residual methanol out of the hexane. I flush like this three or four times. The methanol and water pass through of course and no additional hexane is needed then. I finish always with a water flush to rid hexane of methanol but traces will remain.
After the LLE I personally do an iso boil in more water but make sure first to purge the hexane and trace methanol thoroughly before doing this. Then a room temp or chilled pull through alumina. These two procedures prep the stuff for the sublimator.
After flushing out gunk from 15 L of pentane crude with 15 L of 60% methanol and water, I added pure methanol at 1 part methanol to 1 part pentane/crude solution. Now i have 3 layers again. The black pentane on top has lost a significant amount of volume visually (from 15 L to 5 L). There is a large emulsion layer ( 1 L) . And lastly a giant brown methanol fraction with some yellow precipitation totalling 35 L.
Im trying to pull the cannabinoids into the methanol. What volume methanol is suggested to accomplish this? Im having a hard time wrapping my head around why the cannabinoids would migrate to the methanol
I have only met with marginal success pulling all the cannabinoids into the methanol. I had hoped to pull the cannabinoids into the methanol but so far the exact technique eludes me. Plus my experience is a total of maybe half a dozen labs to test solvent ratios. I found when the methanol is pure and the hexane is pure that the brown seems to catch the cannabinoids. However just a trace of water throws this off. I had thought enough if a ratio might prefer the methanol and therefor the CCE could work. It turns out to be tedious but after twelve tubes it was clear it would take more effort to refine the idea. Pity those old trains of CCE tube could not still be gotten.
I wonder what the third layer is? I have only seen this when a trace of other solvents, like acetone or isopropyl alcohol, is present. Traces of acetone from when I clean almost alway show up as a small third layer but no idea why.
On my botched labs like this I definately just evaporate all the solvent away under best conditions possible then proceed as if from winterization just to salvage. All my stuff gets distilled anyway so a messy LLE is not that big of a problem except the time it takes. I learned on these LLE attempts that don’t work well to not throw out anything when I decide to abort. The THC can hide in both layers when stuff does not go right so I just combine all and evaporate and start from part one of a normal distillation.
LLE is forgiving if it does not go right because it can easily be recovered even if it is a bit messy. You might find that recovering this will also dewax and degum the compound pretty well aa the solvent evaporates away so having a buchner funnel with filter handy can at least make a positive out of a negative. If you have not tossed any liquid then you still have all your compound.
