Constitution of the Alcohols, 95 



In a similar manner a corresponding quantity of pure cyanide 

 of amyle was prepared from sulpho-amylate of potash. 



The cyanides of sethyle and amyle mixed in equivalent propor- 

 tions and dissolved in alcohol, were boiled with an alcoholic solu- 

 tion of potash in excess, until the smell of ammonia, at first 

 disengaged in large quantities, had quite disappeared. The 

 flask in which the fluids were boiled was connected with a 

 Liebig's condensing tube, so that the distilled fluids flowed con- 

 tinually back. It required about thirty hours to finish the 

 operation. 



The solutions of the salt thus formed, containing potash in 

 excess, were evaporated over a water-bath, adding water from 

 time to time to the mixture until all the alcohol was got rid of, 

 finally evaporated to dryness, and then dissolved in a small 

 quantity of water. Sulphuric acid somewhat diluted and in 

 excess was now added gradually, and the mixture kept cool by 

 surrounding the vessel with snow. After standing a short time, 

 an oily layer separated and rose to the surface ; this was sepa- 

 rated by a pipette, well washed with water, and dried over chlo- 

 ride of calcium. 



The Acid soluble in Water. 



The wash-water was added to the fluid from which the oily 

 layer was separated, the sulphate of potash which had been 

 formed being first removed, and the whole then distilled until no 

 more volatile acids came over. The distilled fluids were satu- 

 rated with carbonate of soda, the saline solution evaporated to 

 dryness. The dried salts were placed in a retort, and strong 

 sulphuric acid added by means of a tubulure, very gradually and 

 then carefully distilled. In order to remove a little sulphurous acid 

 from the fluid thus obtained, which was quite soluble in or rather 

 miscible with water, it was agitated for some time with a little 

 dry superoxide of lead. 40 parts of dry carbonate of soda 

 required 88 parts of the volatile acid thus purified for neutral- 

 ization. Of pure propionic acid 84 parts would have been suffi- 

 cient. It contained evidently but a small quantity of another 

 acid with a higher atomic weight ; the smell indicated it to be 

 caproic acid. 



To ascertain if any other acid between the propionic and the 



caproic acids, namely the one sought for, C 9 H 9 O 4 , were present, 

 I submitted the greater portion of the fluid to fractional di- 

 stillation. It began to boil at 105° C, at which temperature a 

 few grammes of acid containing a little water distilled over. The 

 temperature then rose quickly to 140° C, afterwards very slowly 

 to 152°. That distilled between 140° and 150° weighed between 



