94 Prof. Louis Henry on the Polymerization 



CHO , '•• CHC1 2 , rno 



I b.-p. 21°, ^ b.-p. 60°, 



CH 3 CHO 3 



? HGl2 b..p. 140°, V H ° b.-p. 87°. 



CHCIj CH01 a 



In reality, however, glyoxal is only known as a non- 

 volatile viscous mass. It is unnecessary to extend these 

 examples, for the same facts are illustrated in various degrees 

 by all the members of this group (see Bruylants, i On the 

 Polymerization of the Aldehydes/ Inaug. Diss., Louvain, 

 1875). The sell-additive power of methylene oxide, which is 

 so evident in its mono-derivatives, the aldehydes, is less marked 

 in its di-derivatives, the acetones. Though true polymers 

 of acetone itself are unknown, yet those of some of its chloro- 

 derivatives have been obtained by Grabowsky (Per. viii. 

 p. 1438). 



If we compare the boiling-points of the glycollic, aldehydic, 

 and acetonic chlorides with those of the corresponding oxides, 

 thus: — 



OH, 



i 



.CHj.O ... b.-p 



13 



21 

 35 



47 

 56 



CHjCl.CHgOl b.-p. 



CH 3 .CHC1 2 ,, 



CH 3 .CHC1.CH 2 C1 „ 



CH 3 . CH 2 . CHC1 2 „ 

 CH 3 .CC] 2 .CH 3 „ 



84 



oo oo 



WW WW 



.CHO „ 



. CH . CH 2 . „ 



.OH 2 .CHO „ 

 . CO.CH 3 ... „ 



60 

 96 



85 

 70 



and if we further bear in mind the general fact that in the 

 isomeric substituted derivatives of the paraffins, the volatility 

 is the greater when the substitution has taken place in a chain 

 or chains which are least hydrogenated, then we must con- 

 clude that the aldehydes and acetones are only known to us 

 in the state of polymers, which depolymerize completely at 

 the boiling-point. Thus, acetic aldehyde should be gaseous 

 and more volatile than the oxide of ethylene; propionic alde- 

 hyde more volatile than oxide of propylene; and acetone more 

 volatile than the corresponding aldehyde C 3 H 6 0. The real 

 relations are, however, the reverse of these. 



Actual Polymerization of the Oxides themselves. 



The actual polymerization of the oxides is readily indicated 

 by all those characters which have been long observed in the 

 case of the special variety of oxides called by Ohevreul " oxydes 

 cuits." Certain anhydrous and pulverulent metallic oxides, 



