CHAPTER II. 



THE CONDUCTIVITY AND VICOSITY OF SOLUTIONS OF CERTAIN 

 SALTS IN FORMAMID AS A SOLVENT. 



BY P. B. DAVIS AND W. S. PUTNAM. 



The work of Jones and his collaborators in the field of non-aqueous 

 solvents and in mixtures of these solvents with one another, has thus 

 far necessitated a comprehensive study of both the conductivity and 

 viscosity of typical salts in methyl and ethyl alcohols, in acetone, and 

 in glycerol as well as in binary and ternary mixtures of these solvents 

 with one another and with water. A complete review of all this work 

 is to be found in Publication No. 210 of the Carnegie Institution of 

 Washington, Chapter VII. 



Because of the somewhat limited solubility of electrolytes in most 

 organic solvents, the scope of this work has necessarily been somewhat 

 limited in the case of the pure liquids themselves, This is especially 

 true with acetone and the alcohols. Glycerol, however, notwithstand- 

 ing its high viscosity, proved to be a remarkably good solvent. 



Among the few remaining liquids suitable for such work, formamid, 

 the one used in this investigation, is the most important. The fact 

 that it has been studied so little in the past must be attributed to the 

 difficulties encountered in obtaining a product pure enough for con- 

 ductivity purposes. 



Formamid, the first member of the series of acid amids of which aceta- 

 mid is the best known representative, was first prepared by A. W. von 

 Hoffman 1 in 1863, by heating anhydrous ethyl formate with dry 

 ammonia in a sealed tube for some time, and then distilling the resulting 

 product in a partial vacuum. A number of other methods of prepara- 

 tion have been devised, among the earlier ones being that of Behrend, 2 

 who heated a dry mixture of ammonium formate and urea to 140 and 

 purified the oily residue by fractional distillation in vacuo. More 

 recently Phelps and Deming 3 improved Hoffman's method by carrying 

 out the decomposition of the ethyl formate at a temperature below 

 that at which ammonium formate is formed, thereby obtaining nearly 

 the theoretical yield. In addition to the above, probably the most 

 common method of preparing formamid is that depending on the disso- 

 ciation of anhydrous ammonium formate by heat in an atmosphere of 

 dry ammonia, as described for the first time also by Hoffman. 4 By 

 this method, with the latest improvements due to Freer and Sherman, 5 

 pure formic acid is neutralized with dry ammonia and the resulting 



iJourn. Chem. Soc., 16,72(1863). 2 Lieb. Ann., 128, 335 (1863). 3 Centralblatt II, 1604 (1907). 

 4 Ber. d. deutsch. chem. Gesell., 15, 980 (1882). 6 Amer. Chem. Journ., 20, 223 (1898). 



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