Mixe
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Drying agent- which one to choose?
It's a big question I know, and no, I don't have a specific process in mind. As a bit of a n00b, I'm looking for tips and tricks, mnemonics, do's and
donts and rule-of-the thumbs.
I understand to avoid acidic desiccants in basic solutions and vice versa, but when is sulphuric acid a good choice and when is it catastrophic?
My list of available drying agents so far:
Magnesium Sulphate
Calcium Chloride
Calcium Sulphate
Sodium Chloride
Sodium Sulphate
Sulphuric Acid
And I have a bunch of old 3A Molecular Sieves lying around in desperate need of Time In Oven.
So any tips and tricks are appreciated when it comes to the fine art of drying stuff. Either as common chemistry 1.01 or from personal experience.
ELI5 is always good, I have a huge tolerance for being talked down to.
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karlos³
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If you don't have a specific use in mind, look at some compability charts regarding drying agents and solvents.
Because it depends on the situation, as usual.
verrückt und wissenschaftlich
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Mixe
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Thanks.
[Edited on 2021-12-14 by Mixe]
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DraconicAcid
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Calcium chloride is good for non-polar organic stuff, but can really mess up alcohols or carboxylic acids. (We use it in the lab to dry esters, but
we have to use the pellets- if someone accidentally uses the dust, they get a gel.)
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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Mixe
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Ok, thanks! That's just the kind of advice I'm gunning for. I have flakes, hopefully they work as well.
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Texium
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Magnesium sulfate is my go to for almost everything. It’s easy to prepare, it’s easy to store, and it isn’t deliquescent. What more could you
ask for?
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Triflic Acid
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For regenerating your molecular sieves, try microwaving them for 5 minutes. Much faster than oven-dry, but be careful that you don't leave them in too
long, otherwise they'll melt. Apparently molecular sieves above microwaves really well.
There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.
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yobbo II
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See the book:
Purification_of_Laboratory_Chemicals
You can get it here http://libgen.rs/search.php?req=Purification_of_Laboratory_C...
It list drying agents etc
Yob
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macckone
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sodium chloride is not a good drying agent.
potassium carbonate is a fair drying agent for ethanol.
the list posted is completely missing basic drying agents such as sodium hydroxide, sodium metal, and activated magnesium (made by adding a touch of
iodine).
activated aluminum is also a good drying agent (either mercury amalgam or similar, can be used in combination with sodium hydroxide).
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Tsjerk
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Magnesium is also easily activated by stirring for a minute or so in 1% HCl.
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