W. A. Drushel — Hydrolysis of Esters. 69 



Art. VII. — On the Hydrolysis of Esters of Substituted Ali- 

 phatic Acids ; by W. A. Deushel. 



[Contributions from the Kent Chemical Laboratory of Yale Univ. — ecxxxi.] 



S. Ethyl a- and fi-monochlorpropionates, ethyl a- and (3-mono- 

 brompropionates and ethyl aa.-dibrompropionate. 



It was shown by Walden* that the electrolytic dissociation 

 of the brompropionic acids is very much influenced by the 

 position of the halogen with respect to the carboxyl group. 

 DeBarr,f in his investigation of the hydrolytic action of water 

 upon halogen substituted fatty acids, found that the monohalo- 

 gen substituted propionic acids are fairly stable in the presence 

 of water at temperatures below 100° C, and that when decom- 

 position takes place at a higher temperature (150° C.) the posi- 

 tion of the halogen with respect to the carboxyl group has a 

 marked effect upon the velocity of the reaction. The purpose 

 of the present investigation was to study the influence of the 

 position of the halogen on the velocity of the hydrolytic 

 decomposition of the ethyl ester of chlor and brompropionic 

 acids. 



Preparation of Esters. — The ethyl a-chlorpropionate was 

 obtained from Kahlbaum. The ethyl a-brompropionate was 

 prepared by the method of Zelinsky4 The boiling points of 

 the esters having indicated a fair degree of purity, they were 

 analyzed for halogen. Small portions of the esters were 

 weighed into flasks and decomposed with pure potassium 

 hydroxide by warming on the steam bath for twenty-four 

 hours. The solutions were then neutralized with nitric acid, 

 diluted to definite volumes and the halogen estimated gravi- 

 metrically in aliquot portions. Chlorine found, I 26*28 per 

 cent, II 25*91 per cent, mean 26*10 per cent ; chlorine calcu- 

 lated for CH 3 CHCl.COOC 2 H 6 , 25-96 per cent. Bromine found, 

 I 44*37 per cent, II 44-29 per cent, mean 44*33 per cent; brom- 

 ine calculated for CH 3 CHBr.COOC 2 H 6 , 44*18 per cent. 



The /3-halogen substituted propionic esters were prepared by 

 a modification of Richter's method§ for the preparation of 

 /3-halogen substituted propionic acids, which apparently had 

 not heretofore been used for the preparation of the esters. 

 The process for the preparation of the acids depends upon the 

 direct replacement of iodine in /3-iodopropionic acid in water 

 solution by chlorine or bromine. In this process the iodine is 

 said to separate out as free iodine. To prepare the correspond- 



* Walden, Zeitschr. f. phys. Chem., x, 650. 

 f DeBarr, Am. Chem. Jour. , xxii, 333. 

 JZelinsky, Ber., xx, 2026. 

 gKichter, Zeitschr. f. Chem., 1868, 449-451. 



