The crude dichloroacetone is dried in a vacuum desiccator over
sulfuric acid overnight It weighs about 220 g.

The crude product is best purified by distillation from
a 250-cc. distilling flask fitted with an air condenser.
A very small fraction (10-15 g.) of low-boiling material is obtained,
and the dichloroacetone (170-175'0) is then collected. It solidifies
in the receiver to a white crystalline mass which weighs 200-220 g.
(65-70 per cent of the theoretical amount). A few grams more may
be obtained by chilling the low-boiling fraction and filtering
off the water.


2. Notes

Great caution should be exercised in working with dichloroacetone,
as it is extremely lachrymatory and blisters the skin.

In transferring the crystals from the reaction flask to the Buchner
funnel it is necessary to use a certain amount of water to dissolve
the pasty chromium salts which are otherwise quite impossible
to filter. The amount necessary varies greatly in different runs,
according to the manner in which the chromium salts separate.
The amount of this water is kept low in order to dissolve
as little of the product as possible. Nevertheless, 10-15 g.
of dichloroacetone are thus dissolved; this material, together with
a little unchanged dichlorohydrin, may be recovered by a long
procedure involving extraction with ether and sodium bisulfite.
This is not profitable, however.