Acetone adduct?
I’ve been recycling acetone (as drying agent) for quite a while now by means of distillation using a small SS wool packed column without notable
problems. Some of the acetone in my ‘system’ has probably been used several times by now. Some of it has been used to dry ZrOCl2, some for glass,
some for hexachorostannates. Any acetone used for drying purposes gets first treated with CaCO3 to eliminate acidity and then with anhydrous Na2CO3 to
remove most of the moisture. After filtering the crude is then distilled.
But a few days back something unusual happened. Otherwise uneventfully the acetone started coming over at a typical temperature of about 56 – 57 C
at high reflux. I reduced reflux somewhat to speed up distillation and noticed that the collector bottle (which was both clean and dry) sitting on an
ice bath started to, for want of a better term, ‘frost over’. Never saw that before. And it wasn’t the bottom of the flask either: the walls of
the bottle also completely ended up covered in this substance that made the bottle look completely opaque, as if painted clumsily in some murky
varnish. It suggests that the product was created on consensation of acetone vapour, not distilled over…
I soldiered on nonetheless, stopping distillation when the reboiler reached about 80 C BP (at that point on steam bath not much comes over anymore
anyway).
On inspection the distillate flask contained acetone alright but also a solid, slightly gelly looking white mass that was clearly not soluble in the
acetone. Gently rinsing the empty bottle (after decanting off the liquid phase) with some DIW showed that the substance was very water soluble. I’ve
kept the solution for testing but don’t really know what to test for. Is this one of these acetone adducts you hear about?
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