Ethyl Hydracrylate. 119 



the hydrolysis of lactic ester, glyceric ester and the esters of 

 the oxybutyric acids. From an examination of the velocity 

 constants of ethyl propionate, ethyl lactate, ethyl hydracrylate 

 and ethyl glycerate in Table II it is obvious that the effects of 

 alpha and beta hydroxyl groups on the hydrolysis velocity are 

 independent of each other. By comparing the constants for 

 ethyl propionate and ethyl lactate it is seen that alpha hydroxyl 

 here produces a slight accelerating effect at 25° which, how- 

 ever, falls off at the higher temperatures. The beta hydroxyl 

 produces a very marked retardation in the hydrolysis velocity 

 as will be seen by comparing the constants for ethyl propionate 

 and .ethyl hydracrylate. This effect does not fall off materially 

 at the higher temperatures, as is shown by the fact that the 

 ratio of the constants of these two esters is very nearly the 

 same at each temperature at which velocity measurements were 

 made. The combined effect of alpha and beta hydroxyl groups 

 on the hydrolysis velocity is shown in the constants for ethyl 

 glycerate. If the slight accelerating effect of alpha hydroxyl 

 and the very marked retarding effect of beta hydroxyl are 

 both taken into account we would expect the constants for 

 ethyl glycerate to be but slightly larger than those of ethyl 

 hydracrylate at 25°, the percentage of difference falling off 

 slightly at the higher temperature. This expectation is fully 

 borne out by the experimental results. At 25° the constants 

 for ethyl glycerate is 13*5 per cent larger than that of ethyl 

 hydracrylate, at 35° it is 7'9 per cent larger and at 45° the 

 difference is but 2*5 per cent. The velocity constants in 

 Tables I and II were all calculated from the usual titration 

 formula for first order reactions. The temperature coefficient 

 for ethyl hydracrylate is 2*16 for 25° to 35°, and 244 for 35° 

 to 45°. 



Ethyl hydracrylate was also hydrolyzed in N/80 sodium 

 hydroxide solution at 0° and at 25°, and the course of the 

 reaction followed by the titration method fully described in 

 Dean's paper* on the saponification of the esters of other 

 oxyacids. These results are recorded in Table III, and are in 

 accord with the results obtained for the esters of other oxyacids. 



Summary : 1. Hydracrylic acid may be conveniently pre- 

 pared from glycerine by introducing the following modifica- 

 tions into the older methods : oxidation of glycerine by fuming 

 nitric acid and formation of the calcium salt instead of the 

 lead salt ; liberation of the glyceric acid by means of oxalic 

 acid and conversion into beta-iodopropionic acid with iodine 

 and solid yellow phosphorus instead of a carbon disulphide 

 solution of phosphorus ; neutralization of the beta-iodopropionic 

 acid with sodium carbonate before removal of the iodine by 



*Dean, this Journal, xxxv, 605, 1913. 



