fatroucha
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Which reaction can I use to transform 2-hydroxyethyl-triethylammonium bromide to 2-hydroxyethyl-triethylammonium chloride?
We have synthesized 2-hydroxyethyl-triethylammonium bromide, then using it we have tried to prepare other salts. First we have used an ion exchange
column to obtain 2-hydroxyethyl-triethylammonium chloride, after several tries we didn't get any good results. Following this example : [emim][Br] +
KOH -> [emim][OH] + KBr [emim][OH] + CH3COOH -> [emim][CH3COO] + H2O We have tried to prepare 2-hydroxyethyl-triethylammonium acetate but for
some reasons, the reaction didn't take place. Can anyone help me to find an alternative method to synthesize those salts using
2-hydroxyethyl-triethylammonium bromide.
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Boffis
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Use silver oxide instead of KOH you can simply remove the solid silver bromide and then neutralise the solution with acetic acid. In actual fact you
can carry out the neutralization before filtering off the silver bromide. Alternatively you can use silver acetate directly but silver acetate is
sparingly soluble so you have to work with rather dilute solutions. 2-hete hydroxide is a very strong base much like KOH.
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fatroucha
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Using silver oxide seems a good option. Thank you 
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fatroucha
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2-hydroxyethyl-triethylammonium bromide
I have synthesized 2-hydroxyethyl-triethylammonium bromide, I m trying to exchange the bromide to acetate or chloride. Any suggestion please?
I have already tried an exchange column and the following reaction [emim][Br] + KOH -> [emim][OH] + KBr [emim][OH] + CH3COOH -> [emim][CH3COO]
+ H2O , I even have replaced KOH with silver oxide but didn't obtain any results.
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Elemental Phosphorus
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Try reacting it with sodium acetate.
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Nicodem
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Threads Merged
28-3-2017 at 07:22 |
clearly_not_atara
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I think you can do a two-step exchange first with silver perchlorate and then with ammonium X, precipitating insoluble silver halides and ammonium
perchlorate. It'd just be nice to do that without silver perchlorate obviously.
One cheaper possibility is to exploit the solubility and instability of the ion bis(oxalato)borate, (C2O4)2B-. Salts can be produced by the
surprisingly easy method of simply heating a stoichiometric mixture of the corresponding monohydrogen oxalates with additional oxalic and boric acids.
This patent describes a number of methods:
https://www.google.com/patents/US20100145076
Notably, salts of this ion are soluble in many inorganic solvents, but in water, the ion is hydrolysed, and can precipitate calcium oxalate and borate
in the presence of Ca2+. So:
NR4Br + Na(C2O4)2B >> NR4(C2O4)2B + NaBr (s) (organic solvent)
2NR4(C2O4)2B + CaCl2 + 6Ca(CO3H)2 (use as buffer) >> 2NR4Cl + 4CaC2O4 (s) + Ca3(BO3)2 (s) + 6CO2 (g) (aqueous)
The calcium bicarbonate is to prevent a buildup of acid, which stabilizes the oxaloborate ion and prevents calcium salts from forming. It is also very
cheap (limestone + CO2 in water) and acts as a pH buffer.
I haven't done anything like this, but to separate the ammonium from the remaining calcium, I'd heat the solution just below boiling for a few hours
to drive off as much CO2 as possible, then filter off any precipitate (which is mostly limestone) and evaporate the remaining solution to dryness, and
recrystallize the solids with a solvent that dissolves NR4Cl, whatever that is. I've heard that chloroalkanes tend to be good for recrystallizations,
so maybe isopropyl chloride would be a good choice here.
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CharlieA
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Concerning your ion exchange column results: After passing the bromide through the column did you measure the chloride and bromide contents of the
resulting solution (eluant?)
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