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Re: [ccp4bb]: ammonium succinate



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> 
> Dear all,
> 
> As allways an apology for non-CCP4-related questions....
> 
> I looking to buy some ammonium succinate for crystallography, but sofar I only 
> found one ridiculously expensive supplier (ICN, EUR 680 for 100g!) Has anyone 
> been able to obtain normally priced ammonium succinate?

I can beat this price...

For whatever reason, this is not a common item with suppliers.  There are
two ways you can handle this quite cheaply depending on your needs.  Both
involve mixing ammonium hydroxide with succinic acid (as suggested by
another poster).  Both of these components are dirt cheap, and I have done
both methods.

Be careful mixing succinic acid + ammonia as this is an exothermic
reaction.  Do this in a wide open container (a beaker rather than an
erlenmeyer).  You may need to do it slowly or on ice-- it's been awhile
since I've done it.

1)  To make a solution (this is the easier method):  Stir a suspension of
succinic acid in water and add ammonium hydroxide until you reach the
desired pH.  Bring up the volume to the desired FC.

2)  If you must have the solid, that is also possible, but it takes some
more time.  Make a very concentrated slurry of succinic acid in water (the
minimum amount of water-- enough to allow the stir bar to move + allow
mixing, but no more).  Slowly add 2 eq. of ammonium hydroxide (at this
concentration, the reaction may get quite hot so be careful).  Once the
full addition is done, concentrate the solution as much as possible.
Di-ammonium succinate solid can be obtained by recrystallization from hot
H2O/ethanol.  It is very soluble in H2O, so you want the amount of water
to be minimized.  The final product is a very nice robust crystalline
solid after it is dried.

good luck

eric