66 



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



the boiling-points of the ketones mentioned above, although the actual numerical 

 expression of this difference does not coincide with that given by Kolbe. Thus 

 acetone boils at about 55° C, and methylated acetone at 81° C, the difference being 

 26° C. ; and a comparison of the two formula?, 



fCH3 



1 C Me O 



Acetone, 



fCMeHg 

 IC Me O 



V , . 



Methylated acetone. 



shows that acetone is converted into methylated acetone by the substitution of methyl 

 for the^rs^ atom of hydrogen in methyl. Dimethylated acetone, 



fCMe^H 

 LCMeO, 



boils at 93°"5, which is only 12°'5 higher than methylated acetone. An inspection of 

 the formula of this body shows that it is derived from methylated acetone by the sub- 

 stitution of methyl for the second atom of hydrogen in the methyl of acetone. Again, 

 ethylated acetone is derived from acetone by the substitution of ethyl for the first atom 

 of hydrogen in the methyl of acetone, and its boiling-point is 101° or 23° x 2 = 46° 

 higher than that of acetone, whilst the boiling-point of diethylated acetone is 138° 

 or 18°'5 x2 = 37° above that of ethylated acetone. In all cases of isomerism it may be 

 safely asserted that the body containing the fewest atoms of hydrogen replaced by an 

 alcohol radical will boil at the highest temperature. 

 This is clearly seen in the following examples : — 



Name. 



Butyral 



Isomeric 



Methylated acetone 



fCEtHaj 

 ICHO J 



rCMeHgl 

 IcMeO J 



Boiling-pouit. 



95° C, 



81° C. 



Isomeric 



Methyl-butyral . . 

 Ethylated acetone . 

 Ethyl-propionyl . . 

 Dimethylated acetone 



fCrrHJ 

 • ICHO J 



fCEtH2"l 

 IcMeOj 



rCMeHg"! 

 ■ IcEtO J 



fCMe^Hl 

 ICMeO J 



. lire. 



. lore. 



. 101° e. 



. 93°-5 e. 



