( 543 ) 



pi'udiK'ls tliat we have iiot, as yet, succeeded in isolating well-defined 

 compounds. 



Bromine is readily absorbed by it and that in a quantity wliich 

 points to the presence of two double bonds. If we work with a 

 solution of carbon tetrachloride at a low temperature, but little hydrogen 

 bromide is formed. 



From a substance of the formula ('..Hj/)., a great many isomers 

 arc, of course, possible. We cannot enter here into a description of 

 the different experiments made in order to elucidate the structure of 

 the product obtained, but we may state that we have tinally succeeded 

 by means of a synthesis, which leaves no doubt whatever. 



If, on s.-divinyl glycol which, tliaidvS to the beautiful researches 

 of Grinku, may l)e readily prepared, propylaldehyde is allowed to 

 act for 6 days at 90^, a substance is obtained identical with the one 

 described above. 



(Sp. gr. at 12° of the synthetic product 0.9392 

 „ „ „ „ „ „ original „ 0.9416 



Refraction at 12° of the synthetic ,, 1.4434 

 „ „ „ „ original „ 1.4430.) 

 As to the synthetic product, propylidene s. divinylethylene ether, 

 must be given the formula : 

 CH, 



CH 



i 

 CH— 



CH— 0^ 



1 

 CH 



^CH— CH,— CH, 



CH, 



the original must also be considered as a derivative of propylaldehyde. 

 It is, of course, possible that there might be foi-med at first an 

 analogous acraldehyde derivative, which afterwards got converted 

 into a propylaldehyde derivative, but considering the comparative 

 difficulty with which the vinyl grouj) combines with hydrogen, this 

 looks less probable. 



As one of us (v. R.) explained many years ago, s. divinylglycol 

 or 3.4 diliydroxy 1.5 hexadiene would form an excellent material for the 

 preparation of the hydrocarbon CH^ ■= CH — CH == CH — CH = CH,, 

 otherwise hexatriene 1.3.5. 



Different methods which we have tried have not led to the desired 



38 



ProceedlDgs Royal Acad. Amsterdam. Vol. VIII. 



