The Use of Soaps for the Absorption of Bromine Vat or. 

 — By Henry Jermain Maude Creighton, Dr. Sc, 

 Assistant Professor of Chemistry, Swarthmore College, 

 Swarthmore, Pennsylvania, U. S. A. 



(Read 10 May 1916) 



The writer has recently had occasion to investigate a 

 large number of solid substances with regard to their power 

 of absorbing bromine vapor. Of the different classes of 

 substances examined, the following ma}'' be mentioned: 

 soda lime, infusorial earths, solid alcohols, and soaps. The 

 best results were obtained with soaps. 



The absorption capacity of the different substances for 

 bromine was determined as follows: A .slow current of 

 air was first bubbled through liquid bromine and then through 

 concentrated sulphuric acid, after which it was passed 

 through a U-tube containing the finely divided absorbent. 

 To the exit of the U-tube was attached a small calcium 

 chloride tube to prevent any loss of moisture. On leaving 

 the U-tube, the air was conducted through a wash bottle 

 containing a solution of potassium iodide and starch. The 

 first appearance of blue colour in the wash bottle indicated 

 the complete saturation of the absorbent with bromine. 



During the absorption of bromine vapor by some of the 

 .soaps investigated, it was observed that considerable heat 

 was developed in that part of the tube where absorption 

 took place. 



In all cases, it was found that the amount of bromine 

 absorbed by the different soaps varied inversely as the 

 rate at which the gas ,was passed through the absorption 

 tube. For example, when air saturated with bromine was 



(120) 



