video tutorial Potassium cyanide preparation

Summary

• OTC synthesis of cyanide salts using potassium ferrocyanide and potassium carbonate (replacing sodium metal).
• Dry ferrocyanide (8 g) is combined with potassium carbonate (3 g) and heated in a sealed crucible to prevent air oxidation.
• Ferrocyanide decomposes under heat; in the presence of carbonate it yields carbon dioxide, potassium cyanide, and potassium cyanate; iron from ferrocyanide is reduced to iron metal.
• The mixture eventually melts; after cooling and aqueous workup, a pale yellow filtrate is obtained containing cyanide/cyanate and related salts.
• Crystallization by chilling yields a small amount of cyanide-containing solid (about 1.3 g; ~18% yield if pure cyanide), with much product remaining in the filtrate.
• Qualitative tests (copper sulfate, sodium hydrosulfite, and iron complex tests) indicate the presence of cyanide; observations include copper cyanide formation and the Russian blue iron-cyanide complex.
• Conclusion: the method is viable and more OTC-friendly than sodium metal methods; a quantitative yield assessment is needed, and further work may include isolating copper cyanide for weighing. Safety concerns regarding cyanide are emphasized.