M. de Luynes on Butylene. 307 



monobrominated propylene. Several attempts to discover other 

 and easier methods for its preparation have not been successful. 



When bromine is brought into contact with allylene gas in the 

 shade, a limpid mixture of two bromides is obtained, which can 

 be separated and obtained pure by distillation in vacuo. If the 

 action takes place in the light, substitution-products are obtained. 



The first of the above bromides (the bibromide of allylene, 

 G 3 H 4 Br 2 ) is a colourless liquid of a sweetish odour, but whose 

 vapours are very irritating to the eyes. Its density is 2*05 at 0°. 

 It boils at 132°, and is thus readily distinguished from its 

 isomers, dihydrobromic glycide, which boils at 152°, and bibro- 

 minated propylene, which boils at 120°. 



The tetrabromide of allylene, G 3 H 4 Br 4 , forms the greater part 

 of the product of the action of bromine on allylene. It is a 

 colourless liquid, with a pronounced camphorous odour. Its 

 density is 2*94 at 0°, and it boils between 110° and 130° under 

 a pressure of a centimetre. 



Oppenheim finds that iodine combines with difficulty with 

 allylene when the two are exposed in a stoppered vessel to the 

 direct action of the sun. The action is promoted by the use of a 

 solution of iodine, either in bisulphide of carbon or in iodide of 

 potassium. Biniodide of allylene, G 3 H 4 P, is a colourless liquid 

 which decomposes on distillation. Acted upon by bromine, it 

 gives rise to the above bromide. 



Liebermann* has found that when a solution of iodine acts on 

 silver-allylene, a volatile oil with an unpleasant odour is formed, 

 ' which has the composition G 3 H 3 1, and is therefore iod-allylene. 

 On lengthened contact with iodine this substance takes up two 

 atoms of iodine, becoming converted into the body G 3 H 3 1 3 , 

 which is colourless and almost without odour. 



De Luynes found that when erithyrite, C 8 H 10 O 8 , was treated 

 with hydriodic acid, it was changed into a liquid which has the 

 composition of iodide of butyle, G 8 H 9 1 ; it is not, however, 

 identical with this body, but is rather C 8 H 8 , HI, a compound 

 of butylene with hydriodic acid. 



When the above compound is treated with acetate of silver, it 

 yields a liquid boiling between 111° and 113° which has the com- 

 position of acetate of butyle, and another boiling at about 5°. The 

 latter is butylene gas, first obtained by Faraday from the decompo- 

 sition of fatty substances. De Luynes f gives its properties as fol- 

 lows. Gaseous at ordinary temperatures ; it has a peculiar odour. 

 It is but very partially soluble in water, but very much so in 



* Liebig's Annalen, July 1864. 



f Comptes Rendus, vol. lvi. p. 1175. 



