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[The Lycaeum Forums]

 The Lycaeum Forums » Integrate » The Alchemist's Den (Moderator: tryp2fun)Topic:
 Low temperature ghetto style?

[pylkko]

Occasionally gassing is either out of the question or not worth the effort. In places like Volvin's tek freezing/recsrystalization works really well. I'm using mostly n-Hexane due to it's superior qualities. The freezing point of it is -95° C. There are more risks and work in recrystalization, however the freezer only goes to like -20 and that's not very energy efficient even.

So, how do I go down lower, using DIY home methods without going too low, and preferably in an energy efficient, low cost manner?

[luc]

Coldest I think you can get w/o gassing or expensive equipment is like -75-80 C using dry ice.  Liquid N2 is probably you best bet AFAIK.

[pylkko]

Okay, here's an idea: use dry ice in side the freezer. Flash freeze precipitation.

I wonder how much it costs. One of the reasons for avoiding evap and recrystal is €€€

[pharmanimal78]

I'd assume that would work... For a more controlled temp flow I'd also think that chilling IPA etc with dry ice & pumping it through a submerged copper coil would work...

[pylkko]

The idea is to build a cycle: keep the jungle spice always in the np. Flash freeze the pure xtal out, then store the remaining nps with the non-percip xtal for next time. There will also be 12 mg/L H₂O in the case of n-Hexane.

Dry ice is about 5€/kg. Ph. Eur. n-Hexane is about 7€/200 mL IIRC. Evap takes days and gives goo using Volvin method for instance whereas flash would take minutes and give white xtal.

N₂ is too hardcore.

Controlled cooling is a problem. Maybe a styrofoam box inside the freezer to preserve it and the bath upon application. Dry ice is totally np AFAIK. Also it forms a significant amount of CO₂ gas...

[farmerjack]

you can buy dry ice around here at several locations for a dollar a pound, usually in approx 7 pound blocks.

you might be able to put in on a shelf in a large styrofoam cooler and let the cold drop into the bottom of you cooler then put a hole in the styro to regulate the temp if it's too cold. there should be enough room left over in the bottom of the cooler for your other apparatus and hour heavily gloved hands.

this is interesting stuff, do keep us updated.

[pylkko]

Okay, it works in maybe 30 mins, and is just about as easy as an ice bath. Only some extra things to consider: your container might get stuck to the freezing agents. Which is shit, becuase you want to separate the crystals when the container is as cold as possible. This is easy to counter however I found some guide on this on the net, linkposted below. Also, freezers are not really ideal for storing this shit, because they have ventilation and water and whatever else. You need to protect your skin all the time.

In an about -10° C freezer are you can do this in about 8-12 hours with significantly less efficiency. However, if you reuse that same solvent or recristalize it, you will always get more out. So, at the end of the day it all depends on what you think is more of a hassle personally.

http://www.continentalcarbonic.com/dryice/superfreezecanning.php