( 115 ) 



or, of a 2-5-hexadiene : 



CH3— CH=CH— CH,— CH=CH,. 



The first, still having a conjugated system can again absorb two 

 atoms of hydrogen and then yield hexene 3. 



CHg — CHj — CH=CH — CHj — CHj 

 whilst the other one cannot be hj'drogenated any further '). 



The results obtained seem to point out that both reactions have 

 indeed taken place simultaneously, and that the final product of the 

 liydrogenation is a mixture of hexadiene with hexene. 



10 grams of 1-3-5-hexatriene were treated with 100 grams of 

 boiling absolute alcohol and 15 grams of metallic sodium. After 

 the sodium had dissolved, a current of steam was passed, which 

 caused the ready separation of the hydrocarbon formed, which, 

 however, still contained some alcohol. After redistillation, the 

 hydrocarbon was washed with water, dried over calcium chloride 

 and distilled over metallic sodium. 



At 75". 5 it commenced to boil and the temperature then slowly 

 rose to 81°. The liquid was collected in two fractions. 



fraction I. B.p. 75°.5— 78^ Sp.yr.,, 0.7326 jin,, = 1.4532 

 II. „ 78° — 79°.5. „ _ ^, = 1.4665 



These fractions were again united and once more treated with 

 sodium and alcohol. But after purification and drying no liquid of 

 constant boiling point was obtained, for it now commenced to boil 

 at 72°. 5, the temperature rising to 80". The main fraction now 

 possessed the following constants : 



B.p. 72°.5— 74°, Sp.(jr.,, 0.7146 nj)^, 1.4205 



The fraction 75°— 80 gave nn,, 1.4351. 



An elementary analysis of the fraction boiling at 72°. 5 — 74° gave 

 the following result : 



Found Calculated for Cfi^„ Calculated for C„Hj^ 

 C 87.06 87.7 85.6 



H 13.32 12.3 14.4 



The fraction investigated consists, therefore, probably of a mixture 

 of CgHj„ and C,,Hjj. The quantity collected was insufficient to effect 

 another separation. We hope to be able to repeat these experiments 

 on a larger scale as soon as we shall have again at our disposal a 

 liberal supply of the very costly primary material. 



Utrecht, Org. Chem. Lab. university. 



1) If GHo^GH-CHa-CHa-GH^GHa should be formed, this will not readily 

 absorb more hydrogen either. 



8* 



