﻿72 BACON AND FREER. 



the fact that the sodium derivative formed by the action of sodium on 

 acetone, after filtering and washing, was dried in vacuo to constant 

 weight, while at the same time it was wanned to beginning decomposition. 

 If acetone were present in a condition such as the above, it certainly 

 would be driven off by this treatment; nevertheless, the sodium derivative 

 behaved as usual when it was added to dilute acid. That sodium iso- 

 propylate does not behave as does sodium acetone even when it is mixed 

 with acetone is shown by the next experiment. 



Experiment 7. — 2.5 grams of sodium were dissolved in an excess of 

 isopropyl alcohol and diluted with absolute ether. The white color did 

 not change in the least when the derivative was allowed to stand for 

 three hours in an open beaker, whereas the product of the action of 

 sodium on acetone, placed beside it under the same conditions, decom- 

 posed and completely changed in five minutes. When acetone was 

 added to sodium isopropylate under ether, the resulting mixture remained 

 unchanged for a long time when exposed to the air, although after one 

 hour it had assumed a slightly pink tinge. It was now filtered, washed 

 three times with absolute ether, dried and thrown into dilute sulphuric 

 acid. The usual acetone test gave no trace of iodoform. Acetone is 

 therefore not retained by sodium isopropylate. 



Miss Taylor suggests that the reaction first observed by one of us 

 may be due to the formation of the sodium salt of diacetone alcohol 

 (CH 3 ) 2 . COH. CH 2 . CO . CH 3 . This compound is formed from acetone 

 in the cold under the influence of hydroxyl ions. Koelichen 9 has shown 

 that in the presence of hydroxyl ions there is an equilibrium between the 

 amounts of acetone and of diacetone alcohol, thus with a concentration 

 of hydroxyl ions represented by a 10 per cent solution of sodium hy- 

 droxide, the quantity of diacetone alcohol is 3 per cent of the total 

 acetone, and smaller in quantity for a lower concentration of the 

 ions. The sodium compound of this body would contain 1-1.37 per 

 . cent of sodium. We have prepared diacetone alcohol according to the 

 method of Koelichen and subjected it to the action of sodium. The 

 alcohol was diluted with absolute ether and in an open beaker dissolved 

 sodium very rapidly, with marked reddening of the resulting compound, 

 the action resembling closely that observed when acetone is similarly 

 treated in the open air, but on acidifying the product, mesityl oxide and 

 other condensation products of acetone are separated and acetone could 

 be demonstrated in the solution by the formation of its semiearbazone, 

 melting at 185° to 186°. 



A different result is obtained in an atmosphere of dry hydrogen. In 

 the apparatus used in Experiment 1, and under absolute ether, diacetone 

 alcohol is only very slowly attacked by sodium, giving a yellowish sodium 



'Koelichen: Ztschr. f. physikal. Chem. (1900), 33, 129. Heintz: Ann. Chem. 

 (Liebig) (1873), 169, 114. 



