Decomposition of Chloride and Bichloride of Isatin. 193 



monium. By standing, or more rapidly by the application 

 of heat, the solution deposits a white substance, which, if 

 quickly washed with water, freed from air, may be obtained 

 pure. 



Chlorisatyd (chloride of isatyd?) is a white pulverulent 

 substance. When dried at 120° assumes a reddish colour. 

 Insoluble in cold water, but little in boiling water; soluble in 

 boiling alcohol. Formula, C 16 H 10 N 2 CI 2 O 3 , i. e. chloride of 

 isatin plus 2 atoms of hydrogen. It is not changed by the 

 action of chlorine. 



Bichlorisatyd (bichloride of isatyd) is perfectly similar to 

 the protochloride. Formula C 16 H 10 N 2 CI 4 O 3 , i. e. bichlo- 

 ride of isatin plus 2 atoms of hydrogen. 



Bibromisatyd is very similar, C 16 H 10 N 2 Br 4 O 3 . 



Chlorisatyd heated to 180° gives off water, in greater quan- 

 tity at 200°; the remainder in the retort is of a brownish-violet 

 colour. Chloride of isatin sublimes in crystals, and the remain- 

 ing mass evidently contains more of the same, which, as well as 

 the undecomposed chlorisatyd, may be extracted by boiling al- 

 cohol. The insoluble part is pulverulent, dirty violet-coloured, 

 insoluble in water, alcohol and hydrochloric acid ; soluble in 

 caustic potash solution with yellow colour. The alkaline solu- 

 tion gives with hydrochloric acid a yellow precipitate, soluble 

 in boiling water. The violet body is chloride of indin. The 

 composition does not appear to be yet accurately determined. 

 Bichloride of indin is obtained in the same manner, and is 

 quite similar ; bichlorisatyd, as well as bibromisatyd, are de- 

 composed, however, at a lower temperature than the proto- 

 chloride (chlorisatyd). Bibromide of indin is of a deep black- 

 ish red colour, somewhat soluble in alcohol. Chlorisatyd is 

 easily soluble in % solution of caustic potash; out of the solu- 

 tion a salt crystallizes, which is chlorisatinate of potassa; out 

 of the mother liquor acetic acid precipitates a yellow body, 

 soluble in boiling water; by boiling the solution (which has 

 been filtered from the yellow matter so obtained) with hydro- 

 chloric acid, flocks of a brownish violet substance are precipi- 

 tated, precisely similar to the above-mentioned chloride of 

 indin. In the fluid is chloride of isatin. Bichlorisatyd be- 

 haves exactly similar, only that the salt which first crystallizes 

 out is not bichlorisatinate of potassa. Its solution gives with 

 hydrochloric acid a yellowish white precipitate, soluble in hot 

 water, from which it is deposited by cooling. Formula, 

 C 16 H 10 N 2 CI 4 O 4 , i. e. isomeric with the bichlorisatinic acid. 

 The potash salts of these acids are precisely similar ; they 

 differ in their decomposition by hydrochloric acid. The ac- 

 tions of nitric acid and ammonia on chloride and bichloride 



Phil. Mag. S. 3. Vol. 19. No, 123. Sept, 1841. O 



