Section III, 1919 [2571 Trans. R.S.C. 



Note on the Preparation of the Silver Salts of the Fatty Acids and Their 

 Behaviour Towards Ammonia 



By George Stafford Whitby 



Presented by Dr. R. F. Ruttan, F. R.S.C. 



Abstract 



(Read May Meeting, 1919.) 



A simple and convenient method of preparing the silver salts of the 

 fatty acids is found to consist in the addition of an aqueous ammoniacal 

 silver solution to an alcoholic solution of the acid followed by the addi- 

 tion of water. The latter completes the precipitation of the silver salt. 

 Silver palmitate, stéarate, margarate and heptadecylate, and also silver 

 salts of the lower fatty acids, have been prepared by this method. 



If the mixed solution contains excess of ammonia, the silver salt 

 remains in solution. Dilution with water then has the effect of throw- 

 ing the salt out. A number of observations have been made with the 

 object of ascertaining the reason for the precipitating effect of dilution, 

 but hitherto have not led to the formulation of a satisfactory explan- 

 ation. 



The amount of water required to throw out the silver salts 

 depends on the concentration of ammonia present. There is a marked 

 quantitative difference between palmitic and stearic acids in relation 

 to the concentration of ammonia necessary to hold them in solution. 



The analytical applications of the above observations are being 

 studied. 



