Synthesis of sodium ferricyanide

I need to synthesize sodium ferricyanide, $\ce{Na3Fe(CN)6}$, for some benchtop experiments where I don't want any potassium ions in solution. The way I am doing that right now is oxidizing $\ce{Na4Fe(CN)6}$ using sodium permanganate, $\ce{NaMnO4}$, and filtering out the $\ce{MnO2}$ that forms. However, upon reviewing the [SDS](https://www.fishersci.com/store/msds?partNumber=AC459290010&productDescription=SODIUM%20FERROCYANIDE%20DECA%201KG&vendorId=VN00032119&countryCode=US&language=en) for sodium ferrocyanide, I found that strong oxidizing agents are an incompatible material (I am not sure why). Is there a better way to go about doing this synthesis?




As @Maurice said, it can be made by bubbling gaseous chlorine into a sodium ferrocyanide solution. You will obtain sodium ferricyanide plus sodium chloride, which will not disturb further reactions.


$$\ce{2Na4[Fe(CN)6] + Cl2 -> 2Na3[Fe(CN)6] + 2NaCl}$$


There is also [a patent](https://patentimages.storage.googleapis.com/pdfs/US2353782.pdf) which mentioned electrolytic oxidation of sodium ferrocyanide:


$$\ce{2Na4[Fe(CN)6] + 2H2O -> 2Na3[Fe(CN)6] + 2NaOH + H2}$$


You can find a detailed description of the setup in the patent.


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