It will be in both phases.
So what if I first rotovap the mixture, could I then get rid off the excess acetone in the water or will the hydrogen bonding between the acetone and the water make it too hard to evaporate the acetone?
Adding water to water miscible solvent for workup often times produce more trouble than its worth. I would evaporate first next time.
You can try to concentrate your solution on rotovap anyway followed by extraction. If thats not what you want to do, adding enough salt will make the water and acetone separate.
Yes, I learnt it the hard way now.
If I rotovap the acetone off, it would be just water and in theory I should be able to filter off the product.
But what was strange was that I had about 1 liter acetone, and then added 2 liter water and it was still not enough for the product to precipitate out.
Could you explain the addition of salt a bit more and why it makes the product precipitate?
The product has very low solubility in water so adding more water is no large issue if you ask me. It does depend in how large volume we talk about offcourse. Its not so easy to evaporate water so this would not be my first choise.
Maybe if I first give it a go with evaporation, if that can get some acetone out of the mixture, followed by a DCM extraction, followed by a evaporation?
Could try it and see what happens, if I will be able to rotovap off some acetone initially.