First pass solvent remaining after back salting

[A Single Step]

Xylene was used to pull from a basified MHRB solution. The xylene was back salted with citric acid and the DMT citrate solution separated. Afterward there appeared to be a saturated DMT citrate solution with precipitate floating on top. A small amount of xylene made it over to the citric acid solution and sits atop the precipitate. Steps to follow include basifying, pulling with heptane, then freeze precipitation. Would leaving the xylene effect the efficiency of the freeze precipitation? Would it be recommended to allow the xylene to evaporate before proceeding to basification and heptane pulls?

 

[downwardsfromzero]

Xylene can completely ruin a freeze precip.

The xylene here could in principle be removed by adding some heptane, then separating off the NPS. That way, any remaining xylene/heptane mixture will contain less of the stinky xylene than before. Any remaining heptane will evaporate more easily than xylene would and some of the xylene it contains will evaporate at the same time. This can then be repeated with fresh heptane.

If, as it seems, you're having trouble separating the NPS from the water solution, using a vessel with a much thinner neck will facilitate this. Optimally, a separatory funnel would be used for this procedure but not everyone will have access to one of those.