Dr. W . Ramsay on Picoline and its Derivatives. 273 



is mixed with strong aqueous hydriodic acid, and distilled after 

 excess of water has been removed by evaporation, the tempe- 

 rature rises rapidly, and the mass turns brown and viscid. If 

 the distillation be continued, picoline distils over, and the re- 

 sidue, when cool, solidifies to a mass of reddish-brown needles. 

 These needles dissolve in alcohol and in ether, but cannot be 

 recrystallized from either of these solvents ; they are insoluble 

 in carbon disulphide. When brought into contact with water, 

 they melt at once to a deep brown liquid. On analysis this 

 substance was found to have the formula C G H 7 N . I 2 . HI, 

 which requires 80*21 per cent. I. 



0*4300 grm. gave 0*6377 grm. Agl= 80*14 per cent. I. 

 The crystals were analyzed by dissolving them in alcohol 

 and converting the additive iodine into hydriodic acid by sul- 

 phurous anhydride. The melting-point of the diiodide of pico- 

 line hydriodide is 79°. Before the method of preparation 

 which has just been described had been discovered, an attempt 

 had been made to prepare this substance (which is analogous 

 to the bromine compound) by heating picoline with hydriodic 

 acid and iodine in a sealed tube ; but no signs of crystalliza- 

 tion appeared, even when the resulting dark brown liquid was 

 cooled to 0°. As the compound turns liquid when brought 

 into contact with water, this behaviour is explained. 



Action of Chlorine on Picoline. — When chlorine is passed 

 into picoline, the phenomena described by Anderson are seen. 

 The picoline becomes filled with a white nocculent precipitate ; 

 and soon a violent action ensues with great evolution of heat, 

 and the whole mass is transformed into a browii resin which 

 does not admit of purification. If, however, the picoline be 

 poured, in small quantity at a time, into a capacious flask 

 filled with dry chlorine and kept cool, the formation of the 

 resin is avoided, and an oily liquid is formed, which partially 

 crystallizes on cooling ; on addition of water it is changed to 

 a white powder. This powder was collected on a filter, washed 

 with cold water, in which it is very slightly soluble, and dried 

 over sulphuric acid. It agreed in properties with the analo- 

 gous compound obtained from pyridine by Anderson. It has 

 a smell closely resembling that of bleaching-powder, and 

 turned brown on application of heat. Anderson believed it to 

 be the hydrochloride of trichloropicoline, C G H 4 C1 3 N . HC1, and 

 apparently obtained concordant numbers on analysis. He 

 states that it turned brown when heated to 100°, and lost hy- 

 drochloric acid, leaving trichloropicoline. 



This substance was analyzed by combustion with lead elim- 

 inate, as the formula given by Anderson did not appear satis- 

 factory. 



Phil. Mac/. g. 5. Vol. 2. No. 11. Oct. 1876. T 



