viii, a, i Gibbs, Williams, Galajikian: Methyl Salicylate IV 29 



It is evident that equilibrium was practically established in 

 about four hundred hours. 



Cell 2 was opened and analyzed after seven hundred ninety 

 hours at 100°. It showed no internal pressure. The analysis 

 is as follows: 



Aqueous portion. 

 Substance. Gram per 100 ee. 



Free acid, calculated as salicylic 0.0055 



Total salicylic acid 0.96 



Methyl alcohol (by calculation) 0.307 



Methyl salicylate 0.074 



Almost all of the salicylic acid in the aqueous portion was 

 present as alkali salts due to the action upon the glass. 



Methyl salicylate portion. 

 Salicylic acid 0.425 gram per 100 cc. 



The total amount of salicylic acid produced was 1.385 grams 

 per 100 cubic centimeters, which is equivalent to 1.526 grams 

 of methyl salicylate hydrolyzed. 



Method of analysis. — The two layers, water and methyl sali- 

 cylate, were separated and filtered. The salicylic acid in the 

 ester portion was titrated with N/50 sodium hydrogen carbonate 

 solution, employing Congo red as an indicator. The acidity of 

 the aqueous layer was determined in the same manner. The 

 total salicylic acid in the aqueous portion was determined as 

 follows: An aliquot part was made alkaline with sodium hydro- 

 gen carbonate and then shaken out repeatedly with chloroform 

 to remove dissolved ester. It was then acidified with sulphuric 

 acid, and the salicylic acid extracted with chloroform and de- 

 termined colorimetrically. The methyl salicylate in the aqueous 

 solution was determined colorimetrically by the method pre- 

 viously described. 20 



Aliquot parts of the aqueous solution were gently ignited, and 

 the alkali carbonates determined by titration. 



SUMMARY 



The results of the investigation of the saponification of some 

 difficultly soluble esters with sodium hydroxide, and with pure 

 water, in homogeneous and nonhomogeneous solutions and the 

 mathematical considerations involved are described. 



1. Carbon dioxide is found in small amounts as the result of 

 the alkaline, but not of the acid hydrolysis of methyl salicylate 



"Gibbs, This Journal, Sec. A (1908), 3, 357. 



