Phelps and Tillotson, Jr. — Cyanacetic Acid. 277 



using a drop of the solution with logwood paper as a test of 

 acidity. The precipitated salt was then filtered off and the 

 water distilled from the cyanacetic acid and other non-volatile 

 material under diminished pressure by heating the flask in a 

 water bath at 70°-80° and collecting the distillate in a side- 

 necked flask as a receiver, which was kept cool by allowing a 

 stream of water to flow over it continuously. The salt which 

 remained on the filter was washed with 300 cm3 of 96 per cent 

 alcohol, and the alcoholic solution added to the cyanacetic acid 

 residue remaining after the aqueous solution had been distilled 

 under diminished pressure. The mixture was well shaken, 

 filtered, and the salt shaken up with 100 cm3 of alcohol of 96 

 per cent strength, filtered and washed with alcohol. The com- 

 bined alcoholic solutions were then evaporated under dimin- 

 ished pressure, heating the flask in a water bath at 50°-60° 

 and collecting the distillate as before, continuing distillation 

 till the manometer showed 15 mm pressure, to insure removal of 

 all the water. To the residue, which consisted chiefly of cyan- 

 acetic acid and its ester, was added 100 cm3 of absolute alcohol 

 and 5 cm3 of sulphuric acid, sp. gr. 1*84. Then the mass was 

 esterified at 100°-110° for 2*5 to 3 hours with 500 cm3 of absolute 

 alcohol, using the special arrangement of flasks for esterifica- 

 tion described in a former paper* from this laboratory. The 

 crude product was then purified by treating with ice and a 

 solution of sodium carbonate and shaking out with ether. 

 The ethereal solution was then freed from low-boiling pro- 

 ducts and distilled under diminished pressure in the usual 

 manner. 



In experiment (1) of series B, the potassium cyanide and 

 sodium chloracetate were made to react in the cold, the flask 

 standing in ice water for twelve hours. In experiments (1) of 

 series A, and (2) and (3) of series B, the cold alkaline solution 

 of chloracetate, contained in a separating funnel, was slowly 

 run into the hot solution of potassium cyanide. The time 

 employed was fifteen to twenty minutes and the temperature 

 was kept at 90°-95° by the heat of the reaction. In the other 

 experiments of the table the two solutions were mixed immedi- 

 ately and the action allowed to take place vigorously, the 

 temperature being usually about 110°. It has been shown in 

 the former paper to which reference has been made, that this 

 reaction proceeds more smoothly in an alkaline solution at a 

 temperature of about 110°, but these conditions are unfavorable 

 for the production of pure cyanacetic acid or ester, since 

 cyanacetates are converted to malonates in hot alkaline solution. 

 For this reason prolonged boiling after the reaction is over is 

 not desirable. On acidifying, the slight excess of sulphuric 



* This Journal, xxiv, 194. 



