Whats this weird aqueous layer?

How do you get to-70 for so long? I have a chiller that goes to -10. And for winterizing I use dry ice baths that go down to -70 or so at peak. But dry ice is my worst enemy

Thereā€™s freezers that do -70+ and liquid nitrogen, and chillers.

Lots of options

Scavenge the web,auctions,and craigslist for a ultra low freezer they are tha bomb
I find them regularly for around $1000
They make every thing so much easyer
Realy!!!

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How much was your freezer? Did it need to be serviced? @Roguelab

O scooby i scavenge auctions here in europe so diffrent playground
But all freezer i have including the revco Where less than 600ā‚¬ each i collect them :rofl::rofl: dry ice is hard to get often an hour drive or more delivered always 20% less and at 4ā‚¬ a kilo iT s a pain
I have a dry ice maker for the shortpath coldtrap and thats iT
All biomass go under vacuum in the tubes
In the freezer 36" tubes lenght
And then blast away
I also have a -40 freezer to pre freeze iT all so the ultrafreeze doesn t get to stressed

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Service is not often done on a cascade system all service i do myself
Keeping the heat exchangers clean with a vacuum cleaner and Some wd 40 on other parts
Scraping off iceforming with a plastic spatula on the inside once a week and defrosting When neccesary
And last Keeping the sealantt rubbers of the door clean and sprayed with a ptfe lubricant spray

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As other have said an ultralow freezer. We picked up a used one, not sure what we paid for it though.

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So update!

It happened again. Had it under vacuum at 80c or so. I think this stuff has some moisture stuck in it and itā€™s forming a methanol/water blend thatā€™s sucking up some scum and terps LLE style.

Iā€™ll boil it down and test, but that seems like the most likely scenario?

How are you removing the solvent post winterization?

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Rotary evap under vacuum

What vac depth and temp? Even a perfect rotovap will leave solvents behind, but even more so vac and temp are less than ideal.

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Got it up to 28" and 100c before I decided to put it in a sep funnel

Hmm, very weird. Thatā€™s actually harder than we run or rotovap, so I donā€™t think it would be solvent.

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It doesnā€™t freeze either.
Iā€™m still learning towards a water, methanol, terp, scum, fat emulsion.

I think thereā€™s some thc in there as well. But not much. It has a sticky feeling when you rub it in your fingers for a while

Itā€™s only started happening when I switched my winterizing solvent to methanol. I think maybe itā€™s something to do with the lower boiling point of methanol compared to ethanol.

I find this often this layer and i wonder If methanol is. Not an azeotrope but i think iT is a water attractor
Example all tools etc used for bho i rinse in the collection pot after use with methanol If i then pour iT all in a pyrex plate all methanol Will evap off but Will leave me a 10% by volume layer of what You describe and the oil as a separate layer on the botom of the pyrex

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The methanol Iā€™m buying says 99.9% methanol and itā€™s from the hardware store. Do you think itā€™s the 0.1%?

What @Roguelab describing is a result of water molecules being condensed inside the alcohol solution as it evaporates. You will gain a significant amount of water in this way but I know you use a rotovap so that shouldnt be the case, you dont evaporate in the atmosphere so theres nowhere water can come in at those amounts.

Methanol is very hygroscopic like erhanol.

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I live in a remarkably wet climate (BC) so thereā€™s certainly opportunity for moisture to come into the picture.

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The lack of freezing is still puzzling me. I guess thereā€™s minimum 20-30% methanol still in there.

What have you tried so far other than freezing it? Does it boil when you vac it still?

Also this is unrelated but I think u guys will enjoy the read.
https://www.quora.com/What-has-a-higher-IMF-methanol-or-ethanol

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