I had some idea how to simplify ketone purification I wanted to shere.

First thing is non-polar solvent you use for extraction!
When I use toluene/xylene I end up with pristinely pure ketone and better yields,
but most time with DCM I end up with less ketone of worse quality.
Reason is weird basic aezotrope that distilled along ketone.

This is highly pronounced if your extractions contain a little bit of NaOH washes.
Other impurities than hint of DCM and (iso)olefines in such distillate are probably nothing but water
and simple basic compounds like ammonia that were created in reaction of DMF in presence of NaOH.
(Will cover that later if needed...)

Now how to purify this emulsion with ketone from DCM extraction without
additional distilaltions and jield killing reactions?!

It seems to be good idea to add some slightly acid water to the emulsion containing ketone,
and than simply extract it with some fresh DCM!?

In theory water, DMF and big part of (iso)olefin should stay in the acid layer and ketone
should migrate in the DCM that is evaporated easily! Right?!