n(!4 SCIENTIFIC RECORD FOR 1885. 



On the Synthetical Formation of Closed Carhon-chains. Part I — Deriva- 

 tives of Trimethylene (by W. H. Perkins, jr.). — Organic chemistry is 

 generally divided into two distinct sections, namely, the fatty series and 

 the aromatic series. The members of the first series are derivatives of 

 methane, the simplest hydrocarbon, and are characterized by their open 

 or chain form, as, for example, in the case of normal hexane : 



CH, 



CH» 



CH, 



CHs 



I 

 CH4 



I 

 CH3 



Aromatic compounds are, on the contrary, derivatives of a much more 

 complicated basis, namely, of benzene, Celle, which, as was first shown 

 by Kekul6 in 1865, has the constitution : 



H 



C 



/ ^ 



HC CH 



Ji 



HC CH 



\ ^ 



C 



H 



that is, contains a ring consisting of 6 carbon-atoms joined in such a 

 way as to form a regular hexagon. 



These two series differ in the most marked way from one another, the 

 members of the aromatic series being particularly characterized by their 

 extreme stability. 



In considering the differences between these two series, the author 

 says it is a matter of surprise that no intermediate series should be 

 known, the members of which should possess partly the character of 

 fatty and partly that of aromatic com]>ounds. It is quite reasonable to 

 suppose that rings should exist having 3, 4, 5, 7 carbon-atoms as well as 

 6 carbon atoms, though the few experiments made to test this supposi- 

 tion have up to this time failed to throw much light ui)on the subject. 

 Victor Meyer has discussed the improbability of the existence of a 

 3carbon-atom ring : 



Ha 

 C 



/\ 

 HjC— CH2 



which would be isomeric with propylene, OH3.CH.CH2 ; but Reboul, by 

 acting on trimethylene bromide with sodium, obtained a gas which he 

 sujiposed to be ordinary propylene, and Freund has indicated certain 

 reactions of this gas which the author (Perkins) shows are evidences of 

 its being true trimethylene. 



