132 



Studies on Solution. 



anhydride, acetamide, and ethyl acetate by 1 gram-equivalent of 

 water at 100 under the same conditions. The experiments were 

 carried out in the presence of acetic acid. 



TABLE 105. l 



TABLE 106. Hydrolysis of Acetic 

 Anhydride by Water. 



The acetic anhydride was almost entirely decomposed at the end 

 of 1 hour, while the decomposition of the acetamide was slight and that 

 of the ethyl acetate had hardly begun. 



A. and L. Lumiere and Barbier showed that when acetic anhydride is 

 dissolved in water the solution possesses practically all the properties 

 of acetic anhydride itself, but that if 

 more than 12 parts of the anhydride are 

 used solution is incomplete. Table 106 

 shows their results with 5 and 10 per 

 cent solutions of the anhydride in cold 

 water. Aliquot parts of each solution 

 were withdrawn at 10-minute intervals 

 and added to a known slight excess of 

 aniline, which reacted quantitatively 

 with the nonhydrolyzed portion of the 

 acetic anhydride, forming acetanilid and 

 an equivalent of acetic acid. Subse- 

 quent titration with a normal solution of 

 sodium by dioxide gave the total acid 

 present, from which the degree of hydro- 

 lysis of the acetic anhydride was calcu- 

 lated. From their results it can be seen 

 that the rate of hydrolysis is fairly rapid 

 at first and then gradually decreases. It 

 is the more rapid the greater the initial 

 dilution of the anhydride and the higher the temperature. 



Alcoholic solutions of the anhydride were also prepared, and it was 

 found that when molecular proportions were used, esterification was 

 incomplete, even after a month. 



'Bull. Soc. Chim. (Ill) 33, 783 (1905); 35. 625 (1906). 



