in dichloromethane; water K3Fe(CN)6 and Bu4NCl (molar ratio: 1:3) addn. to CH2Cl2/H2O (1:1); stirred 2h; organic layer collected; evapn.; dried; addn. of diethyl ether; stirred several hours; boiled 5-10 min; filtered hot; repeated; removing Bu4NCl in ether soln.; residue dried in oven at 100°C;

in hydrogenchloride Electrochem. Process; equimolar amts. of FeCl3 and ammonium hexacyanoferrate mixing in 0.01 MHCl and electroreducing on a sodium chloride satd. calomel electrode; identified by UV spectrum;