7ii J!'. .1. Drwhel— Hydrolysis of Esters of 



ing ethyl esters, pure ethyl /S-iodopropionate was dissolved in 

 about five times its volume of chloroform and chlorine or brom- 

 ine added in excess, keeping the temperature of the mixture 

 below 50° C. by means of a water bath. Under these condi- 

 tions the iodine is readily replaced by chlorine or bromine with 

 the formation of considerable quantities of chloride or bromide 

 of iodine and the liberation of much free iodine. The chlor- 

 ide or bromide of iodine was removed by shaking the chloro- 

 form solution of ester with water, and the free iodine was then 

 removed by washing with dilute cold sodium carbonate solu- 

 tion and again with water. The chloroform solution of the 

 new ester was dried over calcium chloride and the chloroform 

 removed by warming on the steam bath. The esters so pre- 

 pared were further purified by fractional distillation under 

 diminished pressure. The /3-chlorpropionic ester boiled at 

 162° C. at atmospheric pressure, and the /S-brompropionic 

 ester at 85° C. under a pressure of 25 mm . These esters on 

 analysis by the previously described method gave the follow- 

 ing results : Chlorine found, I 26 - 07 per cent, II 25 - 93 per 

 cent, III 26-00 per cent, mean 26*00 per cent ; calculated for 

 CIT 9 Cl.CH 8 COOC s H„ 25-96 per cent. Bromine found, I 44-10 

 per cent, II 44-20 per cent, III 44-10 per cent, mean 44-13 per 

 cent; calculated for CH,Br.CH 2 COOC 2 H 5 , 44-18 per cent. 



Ethyl aa-dibrompropionate was prepared by a modification 

 of the method of Philippi, Tollens.* In this method it is 

 recommended that 9 parts of bromine be heated with 4 parts 

 of propionic acid in a sealed tube at 190° C. to 220° C. for 24 

 hours, that the hydrobromic acid formed be removed, 9 more 

 parts of bromine be added and the mixture heated for 48 hours 

 at 190° C. to 220° C. A satisfactory yield of aa-dibrompro- 

 pionic acid was obtained by heating at 160° C. for two inter- 

 vals of 6 hours each. Subsequently it was found that the first 

 atom of hydrogen in propionic acid is completely replaced by 

 bromine by heating at 160° C. for two hours. The purified 

 dibrompropionic acid was esterified with absolute alcohol and 

 dry hydrochloric acid in the usual manner. The ester obtained 

 by this method boiled between 102° C. and 103° C. at 38 mm , 

 and on analysis for bromine gave the following results : Brom- 

 ine found, I 61*57 per cent, II 61-54 per cent; bromine calcu- 

 lated for CH 3 CBr 2 COOC 2 H 6 , 61-51 per cent. 



Hydrolysis of Esters. — The ethyl esters of the monohalogen 

 propionic acids were found to be soluble in water only to the 

 extent of about 4 cm3 per liter, and the ethyl ester of aa-dibrom- 

 propionic acid was found to be much less soluble, making it 

 impossible to dissolve enough of this ester in decinormal acid 

 to make satisfactory velocity measurements even at 60° C. In 



* Philippi, Tollens, Ann. d. Chem. u. Pharra., clxxi, 315. 



