Sciencemadness Discussion Board

acetone NaI adduct

Organikum - 2-7-2006 at 07:53

I remember that in the Vogel´s there is mentioned a method for purification of acetone by the soudium iodide adduct.

Bur I am damned if I could find it.

IIRC it simply says adding NaI (don´t remember if in aqueous solution or pure) to actone and putting it in the freezer where the adduct should crystallize. Thats dried and the pure acetone recovered by simply heating.

Has anybody tried this?
Does it work for other compounds, benzaldehyde for example?

Diving into the Vogels again, maybe I can find it.....

/ORG

Organikum - 2-7-2006 at 08:03

Found it, must have been blind:
Quote:

A more convenient procedure is to make use of the addition compound with sodium iodide (NaI,3C3H6O), which decomposes on gentle heating and is particularly well adapted for the preparation of pure acetone. One hundred grams of finely powdered sodium iodide are dissolved under reflux in 440 g. of boiling commercial acetone, and the solution is cooled in a mixture of ice and salt ( — 8°). The crystals are filtered off, and quickly transferred to a dry distilling flask, connected to an efficient condenser and to a receiver cooled in ice. Upon gentle warming, the acetone distils rapidly. Pure acetone has b.p. 56-2°/760 mm., and is highly inflammable.

Zinc - 13-7-2006 at 02:39

Does an acetone/KBr adduct exist?

bio2 - 13-7-2006 at 05:01

Any reason KI wouldn't work here?

Seems any examples of this procedure I have seen always use the NaI.

woelen - 13-7-2006 at 05:23

Most likely you really need NaI. I don't know the precise properties of salt-acetone adducts, but I know that there is a lot of difference in Na- and K-salts with water adducts (hydrated salts).

E.g. K2Cr2O7 is an anhydrous salt, the sodium salt is a dihydrate Na2Cr2O7.2H2O.
K2SO4 is anhydrous, the sodium salt is Na2SO4.10H2O (Glauber salt)

So, I can perfectly imagine that a similar thing is true for acetonated salts.

It can also be the other way around that the potassium salt is more prone to adduct formation, e.g. KF forms a digydrate, while NaF is anhydrous.

Organikum - 13-7-2006 at 13:37

NaI is much more soluble in acetone then KI. Remember Finkelstein!