stoichiometric_steve
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LiClO4 from LiCl with aqueous HClO4?
can i just make LiClO4 from LiCl with 70% aqueous HClO4?
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garage chemist
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Not so easy, you'll have a hard time removing the HCl without decomposing the perchlorate ion.
Precipitate Li2CO3 from LiCl and e.g. Na2CO3 in aqueous solution (Li2CO3 is sparingly soluble), filter, wash, and dissolve in aqueous HClO4 according
to stochiometry. Now you have a pure LiClO4 solution.
Removing the water from this requires more work than just evaporating the solution and putting it in the desiccator. LiClO4 forms a trihydrate that
strongly holds upon its crystal water.
You will have to heat it in vacuum above 100°C for some time to remove the water of hydration.
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not_important
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A note on purifying Li2CO3, especially if you don't want sodium contamination. Stir the Li2CO3 in cold deionised/distilled water and treat with CO2
until saturated. Allow excess Li2CO3 to settle, filter, then bring the filtrate to boiling and filter while hot to collected the purified
precipitated Li2CO3. The filtrate can be used again with more crude Li2CO3 + CO2 for a number of cycles before too much sodium and whatnot builds up
in it.
Lithium carbonate acts similar to CaCO3, it becomes less soluble in hot solution, and forms a more soluble bicarbonate. For that reason wash the
original Li2CO3 precipitate with boiling water, not cold water.
About 5,5 grams of LiHCO3 dissolves in 100 g cold water, Li2CO3 is less soluble :
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stoichiometric_steve
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sorry, i should have been more specific. there is a paper that uses LiBr/LiI for the rearrangement of epoxides to ketones, and i happen to have a kilo
of anhydrous LiCl and dont want to buy any reagent that i could readily prepare myself by anion exchange.
i am not aware if hydrates of LiClO4 are suitable in this kind of reaction, while i'm pretty sure that Cl- wouldnt hurt. maybe the extra protons would
mess things up...
LiBr/LiI are just so expensive, and i guess i dont need much more than 1-5 grams. no need to buy hundreds when u need so little...
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