How do you prepare ammonium iron III sulfate dodecahydrate or ferric ammonium alum CAS 7783-83-7?

Answer 1

Start with iron III chloride or iron II sulfate if you start with iron III chloride add Nh4OH until you get a complete precipitate of Fe (OH)3 next wash the precipitate with some water next add sulfuric acid until all of the precipitate dissolves then evaporate the solution until you get a solid mass of ferric sulfate, wiegh the material and convert to moles, next add some ammonium sulfate in the ratio of 1/1 mole this will give you two mol's of the iron alum. Fe2 (SO4) 3 + (NH4)2 SO4 = 2 FeNH4 (SO4) 2 If you start with iron II sulfate , solid or liquid add some 3% hydrogen peroxide until the exothermic reaction ends then add some NH4OH until you get the same hydroxide as before then follow the same instructions thier is alot of different ways to make this stuff you could also start with rust and react rust with sulfuric acid filter then follow the directions as before, any iron salt will work just oxidize it to the iron III state and react it with ammonia to produce the hydroxide make sure you wash it very well and dont add too much sulfuric acid, better yet leave some hydroxide after you add the acid and filter it out of the solution then evaporate it to dryness then add the (NH4)2SO4 in 1/1 mole ratio. good luck

Answer 2

Ammonia + Sulphuric Acid+ Iron