278 Dr. W. Ramsay on Picoline and its Derivatives. 



which may easily bo obtained some inches long. It is slightly 

 deliquescent, and deflagrates when heated, leaving a bulky 

 residue of charcoal, and evolving a smell of dipyridine com- 

 pounds. 



The methyl sulphate crystallizes with difficulty. 

 The methyl hydrate, prepared from the methyl iodide with 

 moist silver oxide, is colourless at first, but soon turns greenish 

 red. Its properties are analogous to those of the ethyl hydrate 

 described by Anderson. It is decolorized by chlorine ; but no 

 definite compound could be obtained. Anderson stated that 

 the hydrate of ethyl picoline, when boiled, evolved ethylamine ; 

 the distillate from an aqueous solution of about 5 grms. of the 

 methyl hydrate had a peculiar smell resembling leeks, but 

 yielded an unweighably small amount of platinum salt ; so that 

 no reliable results could be obtained on igniting it. The 

 residue from the distillation was evaporated to dryness on the 

 water-bath, and assumed a bright red colour when dry. It 

 had a putrid smell ; and when heated, picoline was evolved, 

 leaving a bulky charcoal. If it is gently heated over an 

 argand lamp, it turns green and iridescent, and dissolves in 

 water with a dull red colour. If bromine is added to an 

 aqueous solution of the hydrate, a resinous precipitate is formed, 

 which dissolves in alcoholic ammonia with a tolerably bright 

 red colour. The red colouring-matter is insoluble in ether. 



Diiodide of 'picoline methyl iodide. — This compound was 

 prepared by dissolving iodine in an alcoholic solution of the 

 methyl iodide, and crystallizes out on cooling in beautiful 

 bluish-black feathery plates which transmit red light. It 

 melts at 129°. After it had been recrystallized from hot 

 alcohol, it was analyzed by decomposing its solution in alcohol 

 with sulphurous anhydride. 



I. 0*2902 grin, of the substance gave 0'4164 grm. of 

 Ag I = 77*54 per cent, of iodine. 



II. 0*3066 grm. of the substance gave 0*4459 grm. of 

 Ag 1= 78*59 per cent, of iodine ; C 6 H 7 N (C H 3 1) I 2 requires 

 77*91 per cent, of iodine. 



The diiodide of picoline methyl iodide is analogous to the 

 diiodide of the hydriodide. It is soluble in alcohol and ether, 

 very sparingly in carbon disulphide, and insoluble in water. 

 Metallic mercury removes the two additive atoms of iodine, 

 with formation of mercurous iodide. 



Picoline ethyl iodide has been described by Anderson. There 

 is, however, one reaction which has not before been noticed : 

 if the ethyl hydrate be treated first with bromine and then 

 with ammonia, a brilliant purple colour is produced, which 

 rapidly fades. I may add that I failed to find ethylamine 

 among the decomposition products of the ethyl hydrate. 



