G_Pig (Newbee)
03-29-01 10:51
No 180979
      Anhydrous Ammonium Acetate or No?  Bookmark   

In Dr. Shulgin's nitrostyrene synthesis from benzaldehyde he uses anhydrous ammonium acetate as the catalyst.  Ammonium acetate is very hygroscopic.  Is it vital that it be dry? 

To dehydrate, considering filtering off the liquid (acetic acid?) (yes, it's VERY wet).  and then dissolve the solid in MeOH, dry with Na2SO4, remove solvent.   My purification of laboratory intermediates book doesn't have anything on this compound.

GP out.
03-29-01 11:55
No 180986
      Re: Anhydrous Ammonium Acetate or No?  Bookmark   

If you vacuum dessicate it for a few days it will be powdery dry.  Just use it quick though, it really does pick up water fast.
03-29-01 12:32
No 180991
      Re: Anhydrous Ammonium Acetate or No?  Bookmark   

Knoevenagel reactions have been covered here before, in many threads. It's well known that the reaction progresses faster and yields are usually better when the water that is formed by the reaction is removed, thus IMHO it would probably be best to start out with as dry of Ammonium Acetate as possible, though it isn't critical. Back in November, drying techniques using a vacuum with a reference for drying AA were brought up in a Methods Forum thread titled: Anhydrous or not.... by modesty  In the future please use the search engine, it saves everyone a lot of time.