28 W. A. Drushel — Hydrolysis of Esters in Fatty Acids. 



grm. of recrystallized monochloracetic acid and 800 cm3 of abso- 

 lute ethyl alcohol containing 1*25 per cent of dry hydrochloric 

 acid gas. The crude ester was separated from the excess of 

 alcohol bv fractional distillation and purified by the method of 

 Phelps and Eddy.* 



Hydrolysis in Deoinormal Hydrochloric Acid. — Purified 

 commercial ethyl acetate, and ethyl cyan acetate and ethyl 

 monochloracetate prepared as described, were hydrolyzed at 

 25°, 35°, and 50° C. by making decinormal solutions of the 

 esters in decinormal hydrochloric acid in 250 cm3 and 500 cm3 flasks 

 fitted with ground glass stoppers and keeping the flasks well 

 submerged in a thermostat during the course of the reactions. 

 The reaction velocity was determined by titrating at intervals 

 25 cm3 of the reaction mixture, diluted with 100 cm3 of cold water, 

 with decinormal barium hydroxide, using phenol phthalein as 

 an indicator. For the purpose of comparing the velocity con- 

 stants the three esters were hydrolyzed under the same condi- 

 tions of temperature and concentration of catalyzing acid. The 

 velocity constants recorded in Table I were calculated as for 

 monomolecular reactions from the titration formula, 



K =-^[log(T.-T.)-log(T„-T.)], 



since cyanacetic and monochloracetic acids are relatively very 

 weak acids in comparison to hydrochloric acid, used as a cata- 

 lyzing acid, although they are many times stronger than acetic 

 acid. The results of the hydrolysis experiments are given in 

 detail in Table I and in summary form in Table III. It will 

 be observed that the velocity constants for ethyl cyanacetate 

 are very much lower than for ethyl acetate and also consider- 

 ably lower than for ethyl monochloracetate, in fact, lower than 

 would be anticipated from the dissociation constants of the 

 three acids, acetic 0*0018, monochloracetic 0*155 and cyan- 

 acetic 0*370. This is the result which may be expected if the 

 molecules of ethyl cyanacetate exist, at least in part, in poly- 

 merized form in dilute acid solution. 



Hydrolysis in Water Solution. — Decinormal solutions of 

 ethyl acetate, ethyl monochloracetate and ethyl cyanacetate in 

 water alone were hydrolyzed at 35° and 50° C. and 25 cm3 por- 

 tions of the reaction mixture were titrated at intervals in the man- 

 ner previously described. In this case the hydrolytic action of 

 water is accelerated only by the acids liberated from the respec- 

 tive esters, a simple instance of autocatalysis. The results were 

 calculated in per cent of ester hydrolyzed at given intervals 

 and are recorded in detail in Table II and in summary form 

 in Table III. It would be expected that the ester which 

 liberates the most strongly dissociated acid would hydrolyze 



* This Journal, xxvi, 253. 



