1877.] 



Transformation of Leucoline into Aniline. 



69 



The acid may be regarded as formed by one or other of the following 

 reactions : — 



(1) C 9 H 7 N+0 2 +H 2 0=C 9 H 9 N0 3 



(2) C 10 H 9 N+O 5 = C 9 H 9 N0 3 +C0 2 ; 



but (1) probably represents the chief source of the acid. Whether per- 

 fectly pure leucoline free from traces of iridoline would give the acid 

 must, however, in the mean time remain an open question, as large 

 quantities of material are required to procure the pure base. The yield 

 of acid only amounts to three per cent, of the bases used. 



Decompositions of the Acid. 

 Action of heat. — The acid heated rapidly above its melting-point becomes 

 dark brown, evolves water, and gives an oily sublimate which ultimately 

 solidifies, leaving a mass of porous carbon. The acid sublimate, which 

 probably contains the anhydride, boiled with water regenerates the 

 acid. 



Action of soda-lime. — The acid heated with soda-lime to a low red heat 

 leaves a deposit of carbon and yields an alkaline oily distillate. This oil 

 is soluble in dilute hydrochloric acid, and gives the characteristic reac- 

 tions of pyrrol. The solution evaporated leaves the hydrochlorates 

 of the bases as a crystalline mass, which, after several solutions and 

 evaporations with dilute hydrochloric acid, is freed from pyrrol. The 

 hydrochlorates of the basic substances produced were now heated with 

 potash, when the bases distilled as a colourless oil. This oil has all the 

 physical and chemical characters of pure aniline. 



In order to demonstrate the transformation of leucoline into aniline 

 the crude product of the oxidation may be used instead of the isolated 

 acid. A cubic centimetre of leucoline dissolved as sulphate, treated with 

 a solution of 3 grams of permanganate of potash, filtered, evaporated to 

 dryness, and the residue mixed with some soda-lime, yields on distillation 

 sufficient aniline to give all its characteristic reactions. If potash-lime 

 be used instead of soda-lime, the product of the distillation is found to 

 be almost free from pyrrol. 



In order to ascertain if any base other than aniline was present, 

 3 grams of the acid was heated with potash-lime and the distillate col- 

 lected in dilute hydrochloric acid. This was fractionally precipitated by 

 chloride of platinum, when 0-1248 gram of the first fraction gave 

 0-0425 gram of platinum, equal to 34-05 per cent., aniline requiring 

 32-99 per cent. The second fraction, 0-2101 gram, gave 0-0688 gram of 

 platinum, equal to 32*74 per cent. 



The only substance associated with aniline seems to be ammonia, as 

 appears from the following experiment, undertaken to ascertain whether 

 any nitrile bases occurred in the distillate. The distillate from other 

 3 grams of acid was collected in nitric acid, and fragments of nitrite of 

 potash added, until all the aniline was decomposed. The solution after 

 being boiled was treated with caustic soda and distilled. The distillate 



