[LookAroundYou]

I am trying to figure out if using a series of Liquid-Liquid extractions would make sense to get rid of an impurity.

Compound A has a solubility of 0.24 g/L in Hexane and a solubility of 0.004 g/L in water. It is in a concentration of about 1000 ppm and I need to push Compound A into the aqueous phase until there is no more than about 5 ppb remaining in the hexane.

How many times would I need to perform the Liquid-liquid extraction to accomplish this feat? I came up with a number around 8000 if I am extracting with equal parts hexane : water each time! This seems like it might not be feasible.

Thanks in advance everyone!

[phth]

Does the extraction efficacy depend on how big the volume of solvent is?

[LookAroundYou]

I think what is more important is the ratio between the two solvents.

[LookAroundYou]

Anyone with a formula that I could use with explanations on how to use it please? I have used formulas that seem to work on scenarios where compounds move from aqueous phase to organic phase. I am using this formula very similarly so I wasn't sure if I was using it correctly.

[Borek]

You know two things:

1. Total amount of the substance doesn't change during the extraction.

2. Ratio of concentrations (as given by the partition coefficient).

That's enough to solve the problem (and derive the requested formula).