E. W. Dean — Hydrolysis of Esters. 605 



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

 phatic Acids; by E. W. Dean. 



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



6. Saponification by Sodium Hydroxide of Hydroxy and 

 Alkyloxy Acetates and Propionates. 



General Discussion. 



Having recently determined the velocity constants of several 

 esters for their hydrolysis in decinormal acid, it was decided to 

 continue the study by measurements taken in alkaline solution. 



Considerable work has been done in this line in connection 

 with the theory of steric hindrance and some of the esters in 

 the list included in this paper have been examined before. 

 Brief mention is made of the researches which have more or less 

 important bearing upon the experiments here described. 



The velocity of saponification of ethyl acetate seems to have 

 been measured first by Warder.* Soon after came a series of 

 very accurate and comprehensive measurements by Keicher.f 

 He determined the relative effects of various bases and also 

 showed that the effect of the alcohol radical in the ester is 

 practically constant. Methyl esters decompose most rapidly and 

 the velocity decreases up the series. The differences, however, 

 are exceedingly slight beyond about the first three members. 

 Reicher's experiments with the esters of different acids pointed 

 toward a decrease in velocity with increasing molecular weight. 



The effect of the presence of neutral salts on the velocity of 

 saponification has been studied by ArrheniusJ and by Arm- 

 strong and Watson. § Measurements have been made by Hjeltjj 

 on esters of polybasic acids and by Goldschmidt^[ on acetacetic 

 ester. The most important work in the present connection is 

 that of Findlay and Turner*"* and Fincllay and Hickmans.ff 

 Here careful determinations have been made of the effect of 

 hydroxyl and alkyloxyl groups on the velocity of reaction. 

 In two cases the esters saponified have been included in the 

 series considered in this paper. The results of this work will 

 be taken up in detail later. 



Preparation of Material. 



The esters used were in general portions of the same samples 

 hydrolyzed in acid solution, results of which workJJ have been 



*Ber., xiv, 1361. \ Ann., ccxxviii, 251. 



% Zeitschr. phys. Chem., i, 110 § Proc. EovalSoc, Series A, lxxix, 564. 



|| Ber., xxix, 110 ; xxxi, 1844. "Tlbicl., xxxii, 3396. 



**Jour. Chem. Soc, lxxxvii, 747. 



ft Ibid., xcv, 1004. {{This Journal, xxxiv, 293. 



