74 II". A. Druskel — Hydrolysis of Esters. 



Summary. — In the presence of decinormal hydrochloric or 

 hvdrobromic acid at temperatures not exceeding 35° C, the 

 ethyl esters of the halogen substituted propionic acids decom- 

 pose almost quantitatively according to the equation : 2 H 4 X. 

 COOaH B +HOH-> C a tf 4 X.COOH + C,H t OH. Below 35° C. 

 the halogen substituted propionic acids decompose very slowly 

 according to the equation : C 2 H 4 X.COOII + HOH -> HX + 

 C„H 4 OH.COOH. When decomposition takes place in this 

 direction the /S position of the halogen favors the reaction. 



When hydrogen is replaced by halogen in the acid group of 

 ethyl propionate the velocity of hydrolysis in the presence of 

 an added catalyzing acid is much less than that of ethyl propi- 

 onate, but in the absence of any added catalyzer it is much 

 greater than that of ethyl propionate. The position of the hal- 

 ogen with respect to the carboxyl group has a marked effect on 

 the velocity of hydrolysis. Esters with halogen in the a posi- 

 tion hydrolyze more rapidly than esters with the halogen in 

 the /S position when the hydrolysis is made in the presence of 

 an added catalyzing acid ; the same is true when the hydrolysis 

 is made in the absence of any added catalyzing acid if correc- 

 tions are applied for the halogen acids set free by the 

 hydrolysis of the halogen substituted propionic acids. 



