August 11, 2020, 06:17:52 AM
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Topic: Can the commercial reusable dry ice packs be used as dry ice in my experiment?  (Read 2688 times)

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Offline 101why?

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I have a few packs of reusable dry ice-gel packs.

They are sent along with the chemicals in a box for keeping the chemicals cool.

Is it possible for me to use that "gel" as dry ice to reach the -78oC (dry ice bath) in one of my experimental step?

P/s: Is there any way to determine the -78oC temperature? As I do not have thermometer that can show the temperature this low.

Thanks.

Offline Dan

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I have a few packs of reusable dry ice-gel packs.

They are sent along with the chemicals in a box for keeping the chemicals cool.

Is it possible for me to use that "gel" as dry ice to reach the -78oC (dry ice bath) in one of my experimental step?

If you can cool the packs down cold enough, then I suppose it is theoretically possible, but it seems like an impractical way of making a cryogenic bath.

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P/s: Is there any way to determine the -78oC temperature? As I do not have thermometer that can show the temperature this low.

If you're using dry ice, the bath is at -78 °C when the CO2 stops subliming.
If you have liquid nitrogen, you can use a frozen EtOAc bath, which is close to -78 °C (EtOAc freezes at -84 °C). We don't routinely have dry ice in our lab, so I use frozen EtOAc instead.
My research: Google Scholar and Researchgate

Offline 101why?

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If you're using dry ice, the bath is at -78 °C when the CO2 stops subliming.
If you have liquid nitrogen, you can use a frozen EtOAc bath, which is close to -78 °C (EtOAc freezes at -84 °C). We don't routinely have dry ice in our lab, so I use frozen EtOAc instead.

Is the liquid nitrogen used to freeze the EtOAc?
Is it possible for me to freeze the EtOAc in an ultra-freezer (able to reach -82oC) and use it, without using liquid nitrogen?
P/s: Our lab has neither dry ice nor liquid nitrogen recently. TT

Would like to know that did you add acetone and NaCl when you are using dry ice to reach -78oC?

Offline Dan

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Is the liquid nitrogen used to freeze the EtOAc?

Yes

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Is it possible for me to freeze the EtOAc in an ultra-freezer (able to reach -82oC) and use it, without using liquid nitrogen?

No. The melting point of EtOAc is -84 °C.

You could look at data tables for common organic solvents and see if you can find something that freezes in the right range. Dimethoxyethane freezes at -69 °C, for example.


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Would like to know that did you add acetone and NaCl when you are using dry ice to reach -78oC?

No NaCl.
My research: Google Scholar and Researchgate

Offline 101why?

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Thanks Dan.

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