SYNTHETICAL EESEAECHES OX ETHEKS. 



53 



C4 



^5 



Na, +CH3l=C4 



O 



OC^H, 



(CHQ a+SNal 



O 



OC2H, 



7^7 



Ethylic dimeth- 

 acetone carbonate. 



Ethylic dimethacetone carbonate is a colourless, slightly oleaginous liquid, possessing 

 a peculiar penetrating pleasant and aromatic odour, and a sharp burning taste. It is 

 scarcely at all soluble in water, but readily so in alcohol or ether. Its specific gravity 

 is '9913 at 16° C. It boils constantly at 184°, and distils unchanged. A determination 

 of its vapour-density gave the following numbers : — 



Weight of ethylic dimethacetone carbonate 



•1993 ffrm. 



Observed volume of vapour 54*09 cub. centims. 



Temperature of bath •. 194° C. 



Height of barometer 76 3 '5 millims. 



Height of internal column of mercury 76'0 millims. 



Height of column of spermaceti 253 millims. reduced to 

 millims. of mercury 



15'7 millims. 



From these data the specific gravity of the vapour was calculated to be 5 "36. The 

 above formula, corresponding to two volumes, requires 5 '45. 



Ethylic dimethacetone carbonate is very slowly acted upon by aqueous solution of 

 potash or soda. A quantity of it was boiled, without any perceptible diminution of its 

 volume, with two separate portions of strong solution of potash for eight or ten hours, 

 an inverted condenser being attached to the flask. 



Alcoholic potash in the cold decomposes it very slowly, but when heated to boiling 

 complete decomposition is effected in a very short time. The action is the same as that 

 of baryta-water. 



Baryta-water instantly attacks ethylic dimethacetone carbonate in the cold, barium 

 carbonate being immediately precipitated. At 100° C. the decomposition is complete in 

 a few minutes ; and on submitting the mixture to distillation, alcohol and a light ethereal 

 liquid pass over. The latter, repeatedly washed with a saturated solution of common salt 

 to remove alcohol, and dried over quicklime, gave on analysis the following numbers : — 



I. '2083 grm. gave "5301 grm. carbonic acid and -2220 grm. water. 

 II. -2594 grm. gave -6572 grm. carbonic acid and -2728 grm. water. 



When the mode of its formation is considered, these results show that the body 

 analyzed is dimethylated acetone, the true homologue of diethylated acetone, and the 

 isomer of ethylated acetone. 



MDCCCLXVI. I 



