Section III, 1917 [107] Trans. R.S.C. 



The Electrolytic Deposition of Iron from Organic Solvents. 



By E. H. Archibald, and L. A. Piguet 



Presented by Dr. D. McIntosh, F.R.S.C. 

 (Read May Meeting, 1917.) 



Berthelot showed, in 1882, that the smallest E.M.F. capable of 

 effecting a decomposition of ferrous sulphate causes the deposition of 

 metallic iron on the negative electrode. No oxygen was evolved, the 

 oxygen generated being used to oxidize the ferrous sulphate to ferric 

 sulphate. When the E.M.F. was raised the oxygen and hydrogen 

 appeared at both electrodes yielding oxide of iron and sulphuric 

 acid. 



The best results dealing with the electrolytic deposition of iron 

 have invariably been obtained when the solutions contained organic 

 acids. Thus, Classen,^ who was one of the first to succeed in quan- 

 titatively depositing iron in a form which could be accurately weighed, 

 employed an oxalate solution containing an excess of ammonium 

 oxalate. In a number of his experiments, while using oxalate solutions, 

 he was able to effect a fairly satisfactory separation of iron from 

 manganese, aluminium chromium and cobalt. 



Citrate solutions were studied by Smith.- He added to the solu- 

 tion an excess of sodium citrate and a little free citric acid. The 

 electrolysis was carried on at 50°C, with a current density of 8 amperes 

 per 100 sq. cm. and an E.M.F. of 7-8 volts. 



Smith and Muhr^ showed later that, if a solution of ammoniacal 

 ferrous tartrate was subjected to the action of a feeble current, equiva- 

 lent to three cubic centimeters of oxy-hydrogen per gas minute, iron 

 separated in compact form but contained carbon. 



One of the difficulties experienced in the above separations was 

 the tendency of carbon to separate with the iron. In all the above 

 methods, according to Avery and Dolis,^ carbon is found in the 

 deposit. 



The fact that in all the cases cited, where the iron was completely 

 precipitated, an organic salt was used, leads one to suspect that 



'Ber. d.d. chem. Gesell. 14, 16, 22 (1881). 

 2Jour. Am. Chem. Soc. 10, 330 (1888). 

 3jour. of Anal. Chem. 5, 488. 

 *Ber. d. d. chem. Gesell., 32, 65, (1899). 



