70 MESSES. E. PEANKLAJsD AND B. F, DUPPA'S 



It is unnecessary at present to follow the development of this reaction further ; but it 

 is evident, from what has been already done, that by a proper selection of the three 

 radicals put into the place of the methyUc hydrogen, any fatty acid, from the margaric 

 downwards, can be produced without difficulty. 



In order to understand the relations between the synthesized and the natural fatty 

 acids, it is necessary to remember the constitution of the latter as revealed in their pro- 

 duction from the cyanides of the alcohol radicals ; these radicals, of which the cyanides 

 have been so employed, must consist of methyl in which not more than one atom of 

 hydrogen has been replaced, since the alcohols containing them yield by suitable oxida- 

 tion the corresponding fatty acids; whereas it has been shown by Friedel* that secon- 

 dary alcohols, such as isopropylic alcohol, in which two atoms of methylic hydrogen 

 have been replaced, yield, under the same conditions, ketones instead of acids. Hence 

 the molecules of the normal alcohol radicals must possess the following constitution : — 



Methyl |^^3 



(CII3 



Ethyl or methylated methyl . . . . -j 

 Propyl or ethylated methyl . . . . ^ ^ 

 Butyl or propylated methyl ....-! 



CMeHg 

 CMeH, 



EtH 



2 



2 

 EtH, 



Amyl or butylated methyl . . . , -j ^ 

 &c. &c. 



CPrHa 

 CPrHa 



C Bu H2 

 BuH 



2 



and hence when the cyanides of these radicals are boiled with caustic alkalies, they yield 

 acids containing as their basylous constituent, the normal alcohol radicals which were 

 present in the cyanides ; thus ethylic cyanide yields potassium propionate — 



(CMeH, (CMeHa P 



IcN Vkho+H3 0=^,oj,o^nh 



v__. .__. (H 



Ethylic cyanide. Potassium 



propionate. 



An inspection of the above formula for potassium propionate shows that propionic 

 acid is incapable of isomerism from any change of radicals ; and, inasmuch as ethyl is 

 simply methylated methyl, it follows that methacetic acid, when obtained by the substi- 

 tution of one atom of hydrogen in acetic acid by one of methyl, must be identical with 

 propionic acid, which, with acetic acid, can have no isomer depending on a difference of 



* Bulletin de la Soc. Chimique, 1863, p. 247. 



