64 MESSES. E. FEANKLAND AND B. F. DUPPA'S 



bodies, for the first does not, according to Chancel, form a definite compound with 

 ammonia, whilst the second does. The two following formulae possibly express the 

 nature of this isomerism : — 



Butyral jCEtH, 



^ Ico: 



"-2 



Butyraldehyde . . . -I ^ 



^ ' ICOH 



If this hypothesis be correct, the first ought to yield on oxidation normal butyric 

 acid, and the second dimethacetic acid. 



When we ascend the ketonic series one step higher, isomerism becomes possible, and 

 the ketonic formula C5 HjoO is susceptible of the three following isomeric modifications: — 



I. II. III. 



[CMeH^ 



"-2 



LCEtO 



jCEtHa fCMogH r( 



ICMeO ICMeO l( 



At first sight it would appear that two other isomers would be produced by the intro- 



rC IT f f ' IT 



duction of propyl (C Et Hg) and isopropyl (C Meg H), thus | p p f ^ and 1 p p '^ n ' ^^^ ^ 



closer inspection of these formula? shows the first to be identical with No. I. and the second 



with No. II. Thus, reduced to the carbonic-acid type, these formulae become respectively 



I. II. 



C Pr Me O C Pr/3 Me O 



All three isomers are now kno^vn. The first of the above formulae is that of ethylated 

 acetone described above, which readily forms a crystalline compound with sodium bi- 

 sulphite. The second is that of dimethylated acetone, which we believe to be identical 

 with the body obtained by Fittig* in distilling lead acetate, and to which he gave the 

 name ethyl acetone. Both bodies form crystalline compounds with sodium bisulphite. 

 The boiling-point of dimethylated acetone is 93°-5 C. Fittig states that ethyl acetone 

 boils between 90° and 95°. The only discrepancy between the two compounds is in 

 their specific gravities, which are as follow : — 



Dimethylated acetone -8099 at 13° C. 



Ethyl acetone "842 atl9°C. 



This discrepancy may perhaps be explained by the fact that Fittig's ketone yielded 

 on analysis 0*6 per cent, too much carbon, and 0*4 per cent, too little hydrogen, which 

 would indicate that it still contained dumasin, from which it had been approximately 

 separated by fractional distillation. 



The name which Fittig has applied to his ketone of the above composition implies 

 that he regarded it as ethylated acetone, but the boiling-jjoint of the latter (101° C.) 

 precludes this supposition (see remarks about these boiling-points below). 



The third of the above formulae is that of FREUND'sf ethyl-propionyl prepared by the 

 * Ann. dcr Ch. iind Pharm. ex. 17. t I^d. cxviii. 1, 



