Fractional freezing

[Nagual]

I just wanted to mention a technique that I haven't seen referenced here yet that could greatly simplify the extraction process. That technique is fractional freezing. Fractional freezing is like distillation in reverse, resulting in precipitation of solids from a solution.

One cheap and easy chemistry trick that will let you perform fractional freezing on almost any solvent is to make liquid nitrogen by placing isopropyl alcohol and dry ice together in a styrofoam cooler.

Pretty much any form of DMT should crash out of solution if you lower the temperature of the solvent slowly enough. An old trick to start nucleation is to scrape a glass stirring rod on the inner surface of the beaker gently.

 

[tele]

Sounds interesting but is it worth the effort when compared to the "traditional method"?

 

[gibran2]

I just wanted to mention a technique that I haven't seen referenced here yet that could greatly simplify the extraction process. That technique is fractional freezing. Fractional freezing is like distillation in reverse, resulting in precipitation of solids from a solution.

One cheap and easy chemistry trick that will let you perform fractional freezing on almost any solvent is to make liquid nitrogen by placing isopropyl alcohol and dry ice together in a styrofoam cooler.

Pretty much any form of DMT should crash out of solution if you lower the temperature of the solvent slowly enough. An old trick to start nucleation is to scrape a glass stirring rod on the inner surface of the beaker gently.

What?

Since when can you make liquid nitrogen with dry ice and isopropyl alcohol? Please provide a legitimate reference. I know that acetone + dry ice will get very cold (not sure about IPA), but without compression, gaseous nitrogen will not condense into a liquid, regardless of temperature.

I’m not sure if you’ve heard of a common DMT extraction technique – it’s often referred to as “freeze precipitation”. It results in precipitation of solids (DMT) from a solution (naphtha + DMT) by lowering temperature.

 

[SnozzleBerry]

This seems to be the source of the confusion...Poor Man's Liquid Nitrogen

As gibran pointed out...dry ice and IPA do not make liquid nitrogen.

 

[gibran2]

Dry ice + acetone or IPA --> -78°C

Liquid nitrogen --> -196°C

source

 

[Thrift]

So you are just adding dry ice to IPA/Acetone that is already saturated with DMT so that it crashes out faster? Or are you using it like an ice water bath?

What sort of vessel are you using to deal with such an extreme change in temperatures? I think an erlenmeyer flask should be able to withstand it.

 

[Dr_Sister]

Be careful what kind of container you stick into an dry ice bath at -78°. A glass one is likely to break from thermal shock unless you can lower the temperature slowly while the beaker is already in pace. The thicker the glass the more likely this problem becomes. Precooling the vessel might mitigate the problem somewhat.