Polymerization during Wiped Film

Dug through the search bar and didn’t see anything that really discussed this topic aside from a few people seeing it during short path distillation.

I’ve noticed a significant polymerization of residue during my wiped film runs and I was curious if some extra processing prior to distillation would have a significant impact in reducing this.

Right now I am extracting in cold ethanol, winterizing, carbon scrubbing, solvent recovery via rotovap then to decarb.

Now when I get to my distillation I will run a first pass for volatile stripping and it’s usually after this first pass when I will start to see some chunks forming but it’s nothing significant. I am running my strip at about 500micron vacuum 140C. But once I get to my second pass this is where it really develops. In fact this past run I did had so much buildup inside it clogged the KF25 elbows and overflowed internally into my distillate side and completely contaminated the distillate with some taffy-like residue.

I was debating adding in a step post decarb where I would water wash with a saturated saline solution (mixing the crude with hexane, then after water washing recover the hexane). Has anyone noticed if this water wash has provided a better distillation experience? As you can see from the attached picture, the time it takes to clean wastes a ton of time.

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What leads you to believe you’re seeing polymerization?

Typically residue from distillate is a rubbery solid.

Cannabinoids, terpenes and a lot of “polymers” are all manifestations of isoprene polymerization. The gunk in the residue section post distillation is just the heaviest “polymers” that existed in the plant at the time of extraction.

Just a guess, but I’d say the activation energy required to induce polymerization would be higher than what is provided in the wiper—also you typically want the feed stream to polymerization to be quite pure or you’ll have side-rxns

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Mmmm caramel

Is it water soluble?

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is this how d8 is produced??

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Isomerize vs polymerize

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It was a joke

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Oof, big social ineptitude moment

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For the both of us :sweat:

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I laughed at both! Thanks

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Mix your decarbed crude with a carrier oil. I have the hve unit too. I use a 2:1 ratio Crude:Canola oil. Itll carry the sugars and resins out without evaporating.

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Yes this makes sense, I just was looking at some potential solutions to limit the amount of this rubbery solid with an extra post-distillation processing step or I very well may need to run my column hotter to keep it in a more flowable state.

I’ve been running wiped film now for maybe 3-4 weeks, a couple runs per week so I’m just starting to get the hang of it. Getting results that are now in the low 80’s with a pretty dark amber color. So I figured I’d throw this out there because the biggest loss in efficiency that I’m seeing so far is the time that goes into cleaning if I get an excessive amount of this residue built up or in the case of the example I posted, it clogs the residue port and builds up inside to the point where it overflows into the distillate side and I need to run it all again after cleaning to clear it up.

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So… I’m lead to believe that often, these weird polymers/residues are actually carmelized sugars. Why? Because they are definitley water soluble and also they literally taste like sweet molasses.

I’ve seen different variations tho of various undesirables in WFE’s they’re not all water soluble and they’re not all sweet.

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is it possible lactic acid is getting carried over in the ethanol and becoming PLA?

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Ahh, that is a very good point!

However, if your upstream extraction processes manage to preclude water-soluble undesirables, it is likely that you can avoid sugars and the like.

Typically this is accomplished using either an alkane or very cold ethanol.

In cases when I’ve extracted too warm, I always end up with a water soluble fraction in my tails.

Another possibility is lack of filtration, which leads to the inclusion of broken trichome fragments…so weird amalgams of epicuticular waxes.

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Its from alcohol extraction. You don’t get this when you LLE into non polar

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@Zoraku

I’ve dealt with what seems to be this exact problem, can you give me some additional details about your run and I’ll try to offer guidance?

  • What system are you using?
  • Vacuum level during distillation?
  • Feed rate?
  • Column and condenser temperature?
  • Do you recirculate your residue back into the feed tank for any period of time?

I’m not sure if it’s your issue, but your pre-refinement might need a little stepping up. There are steps in between de-carb and wiped film/SPD that can be taken to help eliminate sugars and phospholipids. Additionally if you don’t winterize to the fullest you can expect lots of lipids and waxes to build up at higher temps. Perhaps run your machine at a little bit of a lower temp and sacrifice a bit of your cannabinoids to the tails.

@Cannada Thanks for your help, here’s some answers:

  • I am running a single stage HVE wiped film distillation unit
  • During my second pass my vacuum is usually consistent between 60-100 microns
  • Unfortunately I just now got a peristaltic pump to feed with so my feed rate was completely variable based on the viscosity of the material when I would open the feed valve and how far it would be opened. I couldn’t really ever measure it properly.
  • Column has been run around 130-140C and condensor at 75C
  • No depending what the residue looks like it will be tossed or dissolved in ethanol and put back in the process if it looks like I may have some more cannabinoids to capture.

As I mentioned I’ve only run the machine probably 8 or 9 times total so far, so I’m still learning and optimizing parameters.

Also for what it’s worth, I usually extract in ethanol at -80C.

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If you have sight glasses for the residue output side of your WFE, I recommend keeping an eye on them for the viscosity of the residue. Is there a chance the material that is clogging your system is residue that has been dissolved in EtOH and reintroduced to the process?

Based on the information you’ve given me, I think you should run at a higher temp (170c column, condenser should be fine at 75), as well as a slightly higher feed speed if you can control it. When I run into this issue on my system, it’s typically because the material is being fed in too slow and by the time the resin reaches the bottom of the column it’s been stripped of most cannabinoids, and the drop in temperature as it meets the residue pump (which I have set to 90c) results in it turning into the taffy-like mess you’ve shown us above.

Yes now that I have a peristaltic pump I should be able to have a lot more consistent and controllable feed rates into the system. It very well could be some of the residue that I had put back into the process, obviously as I get this system more optimized and running properly there will be less material I should have to put back into the process because I should have less potential cannabinoids on the residue side. Just going through the growing pains right now.

I’ll go ahead and bump up my column temp and wiper speed and see how that works out. I’m running a full stainless steel column and there really isn’t a location where I can put a sight glass - so seeing and knowing what’s going on inside the column isn’t something I can observe visually.