182 
IOWA ACADEMY OF SCIENCES. 
In thinking of possible methods in the synthesis in hand 
perhaps the one first suggesting itself would be as follows. 
It is well known that platinum black has the peculiar 
property of causing hydrogen to unite with other gases, 
without being itself changed. Among the hydrocarbons, 
those thus affected are, in general, only the unsaturated 
ones. 
C — H. 
Acetylene may be structurally represented thus: — |:l 
C — H. 
It will be noticed that there are three bonds uniting the 
two atoms of carbon. Until but one bond remains in this 
position, the compound will be an unsaturated one. If 
acetylene and hydrogen are passed together over platinum 
black, one of the bonds, uniting the two carbon atoms, is 
— C — H 
broken, exposing two free bonds, thus: — C — H. One 
atom of hydrogen now unites with each of the free bonds 
H— C— H 
!i ^ ^ 
forming H — C — H, or O 3 H 4 . The equation of this re- 
action is: 
C3H3^^2H=C3H4....(3). 
C 2 H 4 is a gas called ethylene, or olefiant gas, olefiant 
meaning “ oil forming.” It will be noted that this is also 
an unsaturated compound. A part of it will, therefore, 
suffer further transposition, though all of the ethylene, in 
the majority of cases, may not be so changed. The trans- 
formation will be analagous to that of acetylene and the 
H 
. . i 
H— C— H 
1 
product will be H — C — H, or C^He, called ethane, the 
H 
equation of the reaction being: 
C2H4 + 2H=CsH6....(4) 
