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Lithium Nitrobenzoate Synthesis
I got 4-Nitrobenzoic Acid and Lithium Hydroxide Monohydrate but no solvent that is suited for them, water will take up too much volume, I can't find
any solubility tables the only thing I heard is that Tetrahydrofuran may work but I don't know.
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If you want to prepare the salt lithium 4-nitrobenzoate, have you considered just adding a stoichiometric amount of the 4-nitrobenzoic acid to aqueous
lithium hydroxide, which is very soluble in water? The acid-base neutralization would still occur, and if the product was soluble in water, then all
you would need to do would be to evaporate the water away. If it isn't soluble, then just ensure that you have an excess of the LiOH - to ensure that
no contamination occurs of the original insoluble reactant with the insoluble product.
I used a similar technique when preparing copper acetoxybenzoate (aspirinate), where I added insoluble copper (II) carbonate to a solution of
acetylsalicylic acid to form the insoluble product. I used an excess of the soluble reactant - the acid - to ensure that none of the insoluble CuCO3
ended up in my insoluble product.
Sorry if this is confusing 
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Hmm... How long would it need to react?
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Hexavalent
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I'm not quite sure, but I'd add it portionwise slowly over 30 minutes to an hour. Heating it very gently may help and magnetic stirring (or manual
stirring, if you have no other option) is essential to constantly keep the insoluble reactants in suspension.
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I just got my new hotplate magnetic stirrer a couple days ago, so I'm able to heat and stir as much as needed. But how fast would I stir, how hot
would I heat it, and how would I tell when the reaction is complete?
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Hexavalent
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Only heat very gently, perhaps to 40oC, and simply stir sufficiently to cause all of the insoluble material to be suspended in the liquid
with none settling out.
There's no "easy" way to tell when the reaction is complete, but TLC is probably your best option. Failing that, I'd just try a small-scale run first
- after adding all of your acid, leave it to stir for half an hour - and see where that gets you. If all seems good, then scale up.
[When I used this method, the insoluble reactant and insoluble product were different shades of colour, so determining when the reaction was complete
was pretty easy. However, AFAIK both 4-nitrobenzoic acid and the Li salt are white, so this will be trickier for you.]
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Hexavalent
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Actually, I've just had a thought: following the trends of alkali salts of benzoic acid and other carboxylic acids, your lithium 4-nitrobenzoate may
be soluble in water after all, in which case all you need to do is add a stoichiometric quantity of 4-nitrobenzoic acid solid to a solution of a
stoichiometric amount of LiOH...
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Lithium 4-Nitrobenzoate has decent solubility in water?
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Hexavalent
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I don't know for sure, but I assume so. Try it, and find out! 
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Alright I will share my results!
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Nicodem
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Thread Moved
9-4-2013 at 10:02 |
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