Interesting results from a remarkably dull LLE run

[Neutral]

This is more or less a pt II of the ‘methanol winterization with salt?’, since I no longer need to use only organic ethanol, I can pull out some of my old school techniques that I know many of you here have been using for a while. The obvious being methanol dewaxing as a less equipment intensive winterization needing about -20c. What I was more excited to try was LLE. I come from a chemistry background and I’ve done a lot of LLEs and it is nice to be able to use even simple solvents.

Let’s get to it. For context, I extract with warm ethanol and used a methanol dewax, which did a lovely job pulling a large plug of wax and a fair amount of green leaving the characteristic brown oil. I decided to remove the methanol (65C) water (90C) and decarb (120C) in my rotovap to check my yield and remove some volatiles while I was at it. The oil was smooth with no insoluble material so I let the rotary flask cool to ~90C and poured the oleo into 2 volumes of heptane and a large amount of precipitate formed. At the bottom of the container. Concerned this was cannabinoids, I mixed it thouroughly and transferred the mixtures to 1 gallon HDPE jugs and let them sit overnight. A small amount of the precipitate stuck to the sides so I washed it with a bit of cold heptane and it revealed a red powder!

The powder was readily soluble in water, methanol, slightly soluble in ethanol and acetone, and insoluble in isopropanol (99%), which yielded an orange color characteristic of CBD distillate (though this is THC material). I dissolved some in water and gave it a quick taste (after the heptane evaporated ) and it tasted exactly like a burnt popcorn kernal oddly enough but was not unpleasant even when concentrated.

The next day I had a fritted buchner funnel that I slurry packed a celite cake (200g) followed by a 50g of T1 activated charcoal both suspended in heptane. I didn’t have any bentonite on hand so I just used what I had. I also prefer to filter before my washes as I find this gets a lot of insoluble stuff out and cuts down on aqueous waste.

I performed a standard acid/base wash and I was surprised when the washes all came out clear. I started with ph 4 and 9, so I pushed it a bit and went to 2.5 and 11 just to see if anything would happen and still no color (the quantities I did were 500 mL heptane oleo 2:1, doing 3 50ml washed using citric acid, KOH, both saturated with NaCl). Some of these washed had the slightest yellow-green tinge but nothing I could say for sure.

As a last ditch effort to see something, I decided to do a volatile strip and add 25mL of methanol followed by ~250/500mL of water (done 3 times total). This did yield a brown aqueous/methanol layer and it came out more or less white/yellow on the 3rd wash. After a pH balance and drying over some 4a mol sieves, I passed it through my frit with some celite to filter fine sieve particulate and rotovaped it down. Curious to see how it distills.

Wow. Quite a bit here. Anyone wants to put their best guess foreword, please do. I will as well in a reply, just wanted to keep this shorter. Apologies if this is a redundant thread btw, I’ve read almost every LLE thread I can find and I didn’t see anything on this. Cheers. (images to come soon).

Edit: Added photo of preipitate

[Neutral]

My best guess here is that these are reduced plant carbohydrates & starches that are precipitating out here. There are a few things that tip me off to this. One is the taste of burnt popcorn being the main one as popcorn doesn’t have much in the way of oleochemicals other than oils, but those derivatives are likely heptane soluble. The second is the solubility in water and methanol and the decreasing solubility with the decrease in polarity. Finally, the colors are very characteristic of aldol polymerized ketones/aldehydes and caramelized sugar (oxidized sugar). Their already red color is likely due to the 120C purge/decarb performed before the heptane wash.

I do remember reading that many people mention running into more red colored extracts when winterizing in methanol and this could be a likely culprit is these molecules. Their sparing solubility in ethanol followed by a drop in temperature likely eliminate these from solution. These molecules can likely even make their way into distillate as sugar will begin to dehydrate around 170C right before we start collecting our main fraction. This can generate all kinds of ketones, aldehydes, alcohols, polyols, and conjugated species of the previously mentioned that can certainly co-distill with cannabinoids.

If this is a case the term waxes don’t seem to be the only compound that is being removed in this case!

[Neutral]

The other interesting component of this is that nothing came out in the LLE. I know many people do LLE and remove a lot of colored layers/pigments. Now in my case, I’m not too sure how to get rid of the brown without T5, T41 or W1, but that’s ok as this is going to the still. Now I’m unsure exact what compounds contribute this brown color (I assume oxidized terpenes, cannabinoids and pigments), my best guess is chlorophyll which is rather non-polar and wants nothing to do with water and is content to hang around in the organic phase. Certainly an interesting run!

[Roguelab]

Warm ethanol extracts a sugar rich first demon
Warm ethanol extracts are chlorofyl rich
Warm ethanol is a bi;:&/ to clean up especially if the biomass was old
As for lle it s been a while since I performed these tasks but the red powder I have never seen

[Neutral]

It’s not old material, I’ve never found brown to be an issue when making distillate. Though I suppose there’s levels to the brown.

[highestzen]

Heptane is used in edible oil to determine gum content. It works with hemp and cannabis too. Depending on extraction parameters with a polar solvent, you can have up to 10% gums that are insoluble in heptane. This test does a significant amount of degumming, but if you want to completely degum, LLE is needed.

Edit: adsorbent clays are usually the last step in degumming.

[Neutral]

Interesting, I’ve never run into gums but I know they can be quite red. Though I didin’t filter through a clay the charcoal may have helped; I’m unsure.

If I had some iodine on hand, I could do an indicator test but I don’t. I’ll see what I can get my hands on tomorrow morning. Would be able to rule more definitively.

[anon45638961]

I find charcoal to be annoying and yield robbing. Clays before carbon and carbon only in specific cases where clays fail, such as salvaging a contaminated load by attempting a carbon scrub remediation.

[Neutral]

That seems to be a unanimous opinion for carbon, which is why I decided to use a very minimal amount and only to filter through it, not to scrub. I’m going to filter the remainder just through celite tomorrow and compare. Since the color didn’t improve, I see no reason to do it. I’ll be curious to see if the LLE yields anything else.

[anon45638961]

Celite is a filter aide to remove solids. Won’t do much of anything for any process step that doesn’t immediately come after introducing particulate (such as initial extraction or addition of a scrub). So while you may see the color change from the removal of residual carbon powder, it won’t remove anything else from the distillate mixture.

Also celite and carbon should be rinsed pretty good prior to use. Always filter solvent through the powder til nothing breaches color or solids wise.

[Neutral]

Correct, the celite is there because it is literally the only thing I’ve used that stops carbon from just passing right through (I can’t import photos rn, but my filter is frit, celite, carbon). Since I don’t have any adsorbent clays on hand, I’m using it to filter anything insoluble in the heptane to lighten the load on LLE. And always good to rinse media, though I do neglect it sometimes. I slurry packed both layers with clean heptane and times, and came out no color, just a bit of cloudiness because of water adsorbed by the celite . Second wash came through nice.

[MagisterChemist]

I think your theory is correct that the solids are essentially caramelized sugars, probably gained their color during the decarb step.

[Neutral]

Interesting results followed a few days later. Though I did my final washes with saturated NaCl, I still decided to dry my heptane layer even though it arguably doesn’t matter. I would be boiling off the water with the heptane in this case and purging to ensure an easy distillation, but hey, I’m classically trained as they say. The drying agent I have oodles of is 4A mol sieves (bought a bunch of what I thought was 3A but they were 4A, don’t cheap out on sieves). I left what I had washed in a jug with a bunch of sieves at the bottom over the weekend and when I came back, it was remarkably clear. Here is the side by side.

I think this already is in a handful of threads and is likely similar to a lot of water clear tek where distillation heads and boiling flasks are packed with different powders, but cerainly amazing results from room temperature ethanol.

Note that that isn’t sieve dust, I didn’t move the jug as I didn’t want to disturb the sieves at all. Still going to do a final filtration though.