Easterfield and Taylor. — Hie/her Fatty Acids. 301 



Art. XXXII. — The Interaction of Iron with the Higher Fatty Acids. 



By Thomas H. Easterfield and Clara Millicent Taylor, M.A. (New 

 Zealand Government Research Scholar). 



[Read before the Wellington Philosophical Society, 9th August, 1911.] 



Introduction. 



In a former papei* it was shown that under the action of metallic iron 

 abietic acid is rapidly deprived of its carboxyl group with production of 

 a hydrocarbon. It is well known that the higher fatty acids under con- 

 ditions which should lead to deprivation of a carboxyl group yield ketones 

 more easily than hydrocarbons, according to the equation 



2X • C0 2 H = X 2 CO + C0 2 + H 2 0. 



It therefore seemed probable that heating the higher fatty acids with iron 

 filings would be a simple method for obtaining ketones in good yield. 



Upon heating stearic acid with cast-iron turnings to a temperature 

 of 360-365° C. it was found that over 80 per cent, of the acid was con- 

 verted to stearone. As the usual method of preparing the ketone of stearic 

 acid only gives about 50 per cent, of the theoretical yield, the advantage 

 of the new process is obvious. Another and equally important point is 

 that the quantity of acid which can be treated in one operation is almost 

 unlimited. In the ordinary process of distilling calcium or barium stearate 

 with slaked lime under diminished pressure from a combustion-tube the 

 quantity of ketone prepared in each operation is necessarily small. 



The method was also found to give good yields of ketone with lauric, 

 palmitic, cerotic, montanic, and melissic acids, so that it may be regarded 

 as a general method for the preparation of the ketones of the saturated 

 fatty acids with from 12 to 30 atoms of carbon in the molecule. With 

 acetic, butyric, phenyl-acetic, suberic, and sebacic acids no satisfactory 

 results were obtained. 



The ketones of the higher unsaturated fatty acids have not hitherto 

 been prepared, but the " iron " method allows these compounds to be 

 obtained without difficulty in the oleic series. In the linoleic series no 

 experiments have been made, owing to the difficulty of obtaining the acids 

 in a state of purity. During the progress of these experiments it was 

 pointed out by Mailhef that the vapours of the fatty acids from acetic 

 to stearic acid yield ketones if passed over gently heated " reduced " 

 metals, including iron, copper, nickel, cadmium, and lead. There is, 

 however, an extraordinary difference between the catalytic action of the 

 " reduced " metals (which are in general pyrophoric) and the same metals 

 in the state of powder. (Compare, for example, the inertness of ordinary 

 platinum with the intense catalytic action of platinum-black). Sabatier 

 has, indeed, recently drawn attentionj to the fact that " reduced " nickel 

 exhibits quite different catalytic effects upon mixtures of hydrogen and 

 acetylene, according to the conditions under which the reduction has be3n 

 carried out. 



* Easterfield and Bagley, Trans. N.Z. Inst., vol. 35 (1902), p. 480. 



f Bulletin de la Soc. chimique de Paris, 1909, p. 616. 



j Berich'te d. deutschen chem. Gesellschaft, 1911, p. 1996 



