Counterion exchange

I have a quick question about counterion exchange. I have this very practical problem at my hands that I have a ethyl sulfate $$(\ce{EtSO4-})$$ counterion for a $$\ce{R4N+}$$ moiety ($$\ce{R}$$ = 3 different substituents).

I need to change the counterion to something like a $$\ce{BF4-}$$ or a $$\ce{NO3-}$$. What would be the best approach? What role does the solubility of my $$\ce{R4N+}$$-moiety play? (good solubility in: $$\ce{EtOH},$$ $$\ce{MeOH},$$ $$\ce{DMSO};$$ medium in: water, $$\ce{CH3CN},$$ choloroform; insoluble in: $$\ce{EtOAc})$$

I thought about a classical silver-halide approach where I introduce a silver salt with the fitting counter-ion, but I am afraid that the $$\ce{AgEtSO4}"$$ might be too soluble and that I get silver contamination. ($$\ce{Ag2SO4},$$ for example, has a solubility product of $$10^{-5},$$ whereas $$\ce{AgBr}$$ has $$10^{-13},$$ so there is a big difference.)

Any tips are appreciated!

• Look up ion-exchange resins and papers on ionic liquids. They do a lot of exchange of ions. Nov 22 '19 at 23:53