116 W. A. Drushel — Preparation and Hydrolysis of 



recrystallized from a little hot water, yielding white pearly 

 plates of pure beta-iodopropionic acid. 



To prepare the sodium salt of hydracrylic acid a modifica- 

 tion was introduced into the method of Wislicenus* for the 

 conversion of beta-iodopropionic acid into hydracrylic acid by 

 the action of freshly prepared silver oxide. Sokolowf observed 

 that when a water solution of beta-iodopropionic acid is boiled 

 with freshly prepared silver oxide the iodine is quickly fixed 

 as silver iodide and that in solution are dihydracrylic acid, 

 C 6 H 10 O 5 , and an isomer of this acid besides the hydracrylic acid 

 sought. Moldenhauer^: also made the observation that con- 

 siderable lactic acid is formed in this procedure. In order 

 to avoid the formation of lactic acid and the acids identified by 

 Sokolow, Wislicenus heated his solution below 100° while fix- 

 ing the iodine by means of silver oxide. The silver which 

 combined with the hydracrylic acid formed in the reaction he 

 removed by means of hydrogen sulphide, neutralized the acids 

 in solution with sodium carbonate and evaporated to complete 

 dryness. From the dry mixture of sodium salts Wislicenus 

 extracted sodium hydracrylate with boiling 95 per cent alcohol, 

 leaving in the residue the sodium salts of Sokolow's acids. 



It was found preferable to modify this procedure by neu- 

 tralizing the beta-iodopropionic acid with sodium carbonate, 

 and then removing the iodine by acting upon a concentrated 

 solution of sodium beta-iodopropionate with a slight excess of 

 freshly prepared silver oxide at room temperature, making use 

 of mechanical stirring during the process of replacing the 

 iodine by the OH group. To remove completely the iodine 

 from the sodium salt of 400 grms. of beta-iodopropionic acid 

 by this procedure required about two hours, but the resulting 

 sodium hydracrylate was apparently free from the salts of the 

 acids formed by the older methods and identified by Sokolow 

 and others. After the complete fixation of the iodine as indi- 

 cated by no further change in the color of silver oxide when 

 added to the solution, the precipitated silver iodide was filtered 

 off and the filtrate evaporated to complete dryness over the 

 steam bath. It is important that the sodium hydracrylate 

 should be evaporated to complete dryness in order to be able 

 to purify the salt by crystallization from 95 per cent alcohol. 

 The dried residue of sodium hydracrylate was dissolved in 

 boiling 95 per cent alcohol, and allowed to crystallize out on 

 cooling. The residue of sodium salt was completely dissolved 

 by the hot alcohol, indicating the absence of the sodium salts 

 of Sokolow's acids. The crystallized sodium hydracrylate was 

 treated with a little less than the theoretical amount of dilute 



* Wislicenus, Ann. Chem. Pharm., clxvi, 10. 



f Sokolow, ibid., cl, 167. 



\ Moldenhauer, ibid., clxvi, 10. 



