66 



Extraction of salicylic acid from different viine?. 



[Salicylic acid found.] 

 BY MEANS OF CARBON TETRACHLORID. 



BY MEANS OF TOLUENE. 



SHORT METHOD FOR THE QUANTITATIVE DETERMINATION OF SALICYLIC ACID. 



From the results of the qualitative test made by Mr. Ash it appeared that it would 

 be advantageous to confine the work with the quantitative method to carbon tetra- 

 chlorid and toluene. Accordingly, Mr. Ash applied the method to various types of 

 wine containing known amounts of salicylic acid varying from 2.5 to 100 mg per 

 100 cc. One hundred cubic centimeters of the wine were acidified with 5 cc of sul- 

 phuric acid (1 to 3) and 50 cc of the solvent were added, gently but thoroughly mixed, 

 and the solvent separated after centrifuging; 25 cc of the solvent were transferred 

 to a weighed watch glass by means of a pipette. With toluene the best results were 

 obtained using a watch glass 4.5 inches in diameter and with carbon tetrachlorid 

 one 4 inches in diameter. 



The solvent was allowed to evaporate spontaneously and the amount of residue 

 determined by weighing. The residue was then dissolved in 5 cc of neutral alcohol 

 and transferred into a small casserole, the watch glass being washed thoroughly with 

 neutral boiling water and the salicylic acid titrated with one-hundredth normal barium 

 hydroxid, 1 cc of the reagent being equal to 1.38 mg of salicylic acid. 



An aliquot part of the solvent was allowed to evaporate spontaneously, the residue 

 dissolved in 2 or 3 cc of alcohol and diluted with water sufficiently for the colorimetric 

 determination with ferric chlorid. When the amount of salicylic acid present in the 

 original sample was not less than 25 mg per 100 cc, the results obtained by weighing and 

 titration were far superior to those obtained by the colorimetric method, but with 

 smaller amounts the last method was the only one applicable. No tannin was found 

 in any of the residues and the ferric chlorid reactions were clear and entirely charac- 

 teristic of pure salicylic acid. 



In the gravimetric and volumetric determination small amounts of soluble sub- 

 stances were extracted by the solvent. The weight of the residue from 25 cc of the 

 solvent used in extracting normal wine varied from 2 to 3 mg and its acidity was equal 

 to about 0.5 cc of one-hundredth normal barium hydroxid. The results obtained 

 by Mr. Ash on different types of wine are given in the table. In each case these 

 results are the average of three closely agreeing determinations. 



