Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: aranel on November 27, 2009, 10:16:39 AM
-
to make triethylammonium phosphinate, i mixed triethylamine and hypophosphorus acid (50 %) together, and i have to remove the water now to end up with the salt. i tried coevaporating with toluene, but simply doesnt work. >:( any practical ideas? thanks :-[
-
well anyway i increased the temp of the waterbath up to 60. i will wait and see. it has to evaporate ;D
-
you can use a lyophilizer (Freeze Dryer) to remove the water if you can find one. If there is a nearby biochem lab or any lab that does lots of reverse phase HPLC they will probably have one. Otherwise, if your material is stable to alcohols you could find a lower boiling alcohol to azeodry with, then azeodry out the ethanol with aprotic organic solvent.
-
Does the stability of the compound preclude rotovaping? I am not familiar with this class of compounds...
-
i dont think rotavap would harm anything. in the end it's a salt.
my supervisor suggested drying it through diphospho pentoxide in a dessicator. that's what i am doing right now.
if the compound remains to look like an oil afterwards, i would assume it is water free but for some reason not crystalizing. ::)
-
kughelror?
-
Yes I would shell freeze it in an ethoxyethanol slush bath then attach it to a manifold or a simple oil pump with a protective resovoir (to collect the water) then simply let it freeze dry overnight. Some people have freeze drying kits but I used to do this a lot just on a manifold with a freeze dry apparatus. It can produce some lovely albeit somewhat quite static solids. The drying in vacuo over P2O5 is fine if your compound doesnt contain much water as the P2O5 soon forms a cake over the top and you have to replace it a lot. I used to also dry salts by reluxing with thionyl chloride but again this is just for traces of water...
Have you solved it yet?
R