536 MM. Borsche and Fittig on the Preparation of Allylene. 



way acetone was obtained pure, as evidenced by its boiling-point, 

 its analysis, and its combining with sulphite of soda. 



Borsche and Fittig*, in an investigation of acetone, describe 

 some of its derivatives, and a new mode of converting that body 

 into allylene gasf- When chlorine is passed into acetone, hydro- 

 chloric acid is formed, which remains dissolved in the acetone. 

 On distilling the liquid, torrents of hydrochloric acid are given 

 off, and a distillate is obtained consisting of unchanged acetone 

 along with dichlorinated acetone, € 3 H 4 CI 2 0, a body which, when 

 suitably purified, has a pleasant ethereal odour, and boils at 120°. 



When this body is treated with pentachloride of phosphorus, 

 it is acted on in the same way as is acetone ; that is, it exchanges 

 its atom of oxygen for two of chlorine. 



The decomposition takes place according to the equation 



€ 3 H 4 C1 2 + PC1 5 =C 3 H 4 C1 4 + PC1 3 0. 

 Dichlorinated Chloride of di- 



acetone. chlorinated acetone. 



The reaction requires, however, for its completion a lengthened 

 action of the pentachloride. The new compound, G 3 H 4 CI 4 , is 

 a colourless oil of not unpleasant odour, which boils at 153°. 

 It is isomeric with Cahours's quadrichlorinated propylene, the 

 boiling-point of which, however, is about 50° higher. 



When chloride of dichlorinated acetone is treated with either 

 caustic potash or ammonia, it is resolved into a body, G 3 H 3 CI 3 , 

 which is isomeric but not identical with trichlorinated propylene, 

 and which Borsche and Fittig call isotrichlorinated propylene. 



From its formula, chloride of dichlorinated acetone can be 

 regarded as the chloride of atetratomic hydrocarbon, C 3 H 4/, "C1 4 ; 

 this is, in fact, the case; the hydrocarbon is the gas allylene. 

 The action of sodium on the chloride is at first feeble, soon 

 begins to be extremely violent, and requires to be moderated. 

 It was found best to dissolve the chloride in four times its 

 volume of rectified benzole before adding the sodium; by warm- 

 ing or by cooling, the action could then either be accelerated or 

 moderated. The allylene was given off as gas, and was absorbed 

 by passing it into an ammoniacal solution of subchloride of cop- 

 per, with which it forms a well-defined compound — copper- 

 allylene. When this compound was treated with hydrochloric 

 acid, allylene gas was disengaged, the identity of which was de- 

 termined by converting it into the bromide, € 3 H 4 Br 2 , and the 

 tetrabromide, C 3 H 4 Br 4 , already described by OppenheimJ. 



* Liebig's Annalen, January 1865. f Vide anfea, p. 306. 



X Ibid. p. 307. 



